diff --git a/src/core/lcurses/xmake.lua b/src/core/lcurses/xmake.lua
index 6945c14..8319931 100644
--- a/src/core/lcurses/xmake.lua
+++ b/src/core/lcurses/xmake.lua
@@ -1,5 +1,5 @@
 target("ltui")
-    
-    -- add source files
-    add_files("lcurses.c", {languages = "c99", cflags = "-Wno-expansion-to-defined"}) 
+
+    -- add source files
+    add_files("lcurses.c", {languages = "c99", cflags = "-Wno-expansion-to-defined"})
 
diff --git a/src/core/pdcurses/xmake.lua b/src/core/pdcurses/xmake.lua
index 0bcb9a8..b2b5ce6 100644
--- a/src/core/pdcurses/xmake.lua
+++ b/src/core/pdcurses/xmake.lua
@@ -1,7 +1,7 @@
 target("ltui")
 
     -- add source files
-    add_files("**.c") 
+    add_files("**.c")
 
     -- add defines
     add_defines("PDC_WIDE")
diff --git a/src/ltui.lua b/src/ltui.lua
index 0ee4560..63d2147 100644
--- a/src/ltui.lua
+++ b/src/ltui.lua
@@ -12,7 +12,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
diff --git a/src/ltui/action.lua b/src/ltui/action.lua
index 98e1c0a..544f377 100644
--- a/src/ltui/action.lua
+++ b/src/ltui/action.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -37,8 +37,8 @@ function action:register(tag, ...)
 end
 
 -- register action enums
-action:register("ac_max", 
-                "ac_on_text_changed", 
+action:register("ac_max",
+                "ac_on_text_changed",
                 "ac_on_selected",
                 "ac_on_resized",
                 "ac_on_enter",
diff --git a/src/ltui/application.lua b/src/ltui/application.lua
index ef25710..a145823 100644
--- a/src/ltui/application.lua
+++ b/src/ltui/application.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -59,7 +59,7 @@ function application:exit()
     log:flush()
 end
 
--- get menubar 
+-- get menubar
 function application:menubar()
     if not self._MENUBAR then
         self._MENUBAR = menubar:new("menubar", rect{0, 0, self:width(), 1})
@@ -96,7 +96,7 @@ function application:on_resize()
     program.on_resize(self)
 end
 
--- run application 
+-- run application
 function application:run(...)
 
     -- init runner
diff --git a/src/ltui/base/dlist.lua b/src/ltui/base/dlist.lua
index 9504d22..adcc8d4 100644
--- a/src/ltui/base/dlist.lua
+++ b/src/ltui/base/dlist.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -176,7 +176,7 @@ end
 
 -- get items
 --
--- .e.g 
+-- .e.g
 --
 -- for item in dlist:items() do
 --     print(item)
diff --git a/src/ltui/base/log.lua b/src/ltui/base/log.lua
index 6f483f1..e95ad54 100644
--- a/src/ltui/base/log.lua
+++ b/src/ltui/base/log.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --o
 -- @author      ruki
@@ -26,10 +26,10 @@ function log:file()
 
     -- disable?
     if self._ENABLE ~= nil and not self._ENABLE then
-        return 
+        return
     end
 
-    -- get the output file 
+    -- get the output file
     if self._FILE == nil then
         local outputfile = self:outputfile()
         if outputfile then
diff --git a/src/ltui/base/os.lua b/src/ltui/base/os.lua
index 5c498af..21f04f3 100644
--- a/src/ltui/base/os.lua
+++ b/src/ltui/base/os.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -72,7 +72,7 @@ function os.host()
         elseif package.config:sub(1, 1) == '\\' then
             os._HOST = "windows"
         else
-            local result = os.iorun("uname") 
+            local result = os.iorun("uname")
             if result then
                 if result:lower():find("linux", 1, true) then
                     os._HOST = "linux"
diff --git a/src/ltui/base/path.lua b/src/ltui/base/path.lua
index 50a2eb0..18195af 100644
--- a/src/ltui/base/path.lua
+++ b/src/ltui/base/path.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -104,7 +104,7 @@ end
 
 -- convert path pattern to a lua pattern
 function path.pattern(pattern)
-    
+
     -- translate wildcards, .e.g *, **
     pattern = pattern:gsub("([%+%.%-%^%$%(%)%%])", "%%%1")
     pattern = pattern:gsub("%*%*", "\001")
diff --git a/src/ltui/base/string.lua b/src/ltui/base/string.lua
index fe25fba..8e8b831 100644
--- a/src/ltui/base/string.lua
+++ b/src/ltui/base/string.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -22,7 +22,7 @@
 local string = string or {}
 
 -- match the start string
-function string:startswith(str) 
+function string:startswith(str)
     return self:find('^' .. str) ~= nil
 end
 
@@ -96,7 +96,7 @@ function string:append(substr, separator)
     else
         s = string.format("%s%s%s", s, separator or "", substr)
     end
-    
+
     -- ok
     return s
 end
@@ -152,7 +152,7 @@ function string.tryformat(format, ...)
     end
 end
 
--- case-insensitive pattern-matching 
+-- case-insensitive pattern-matching
 --
 -- print(("src/dadasd.C"):match(string.ipattern("sR[cd]/.*%.c", true)))
 -- print(("src/dadasd.C"):match(string.ipattern("src/.*%.c", true)))
@@ -167,7 +167,7 @@ function string.ipattern(pattern, brackets)
     local tmp = {}
     local i = 1
     while i <= #pattern do
-        
+
         -- get current charactor
         local char = pattern:sub(i, i)
 
@@ -184,7 +184,7 @@ function string.ipattern(pattern, brackets)
                 i = i + 2
             end
         -- brackets?
-        elseif char == '[' then 
+        elseif char == '[' then
             tmp[#tmp + 1] = char
             i = i + 1
             while i <= #pattern do
@@ -193,12 +193,12 @@ function string.ipattern(pattern, brackets)
                     tmp[#tmp + 1] = char
                     tmp[#tmp + 1] = pattern:sub(i + 1, i + 1)
                     i = i + 1
-                elseif char:match("%a") then 
+                elseif char:match("%a") then
                     tmp[#tmp + 1] = not brackets and char or char:lower() .. char:upper()
-                else 
+                else
                     tmp[#tmp + 1] = char
                 end
-                if char == ']' then break end 
+                if char == ']' then break end
                 i = i + 1
             end
         -- letter, [aA]
diff --git a/src/ltui/base/table.lua b/src/ltui/base/table.lua
index 504c058..59ee9ca 100644
--- a/src/ltui/base/table.lua
+++ b/src/ltui/base/table.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -24,7 +24,7 @@ local table = table or {}
 -- clear the table
 function table.clear(self)
     for k in next, self do
-        rawset(self, k, nil) 
+        rawset(self, k, nil)
     end
 end
 
diff --git a/src/ltui/border.lua b/src/ltui/border.lua
index 5c5720f..79439f0 100644
--- a/src/ltui/border.lua
+++ b/src/ltui/border.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
diff --git a/src/ltui/boxdialog.lua b/src/ltui/boxdialog.lua
index c46a0aa..8e6691a 100644
--- a/src/ltui/boxdialog.lua
+++ b/src/ltui/boxdialog.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
diff --git a/src/ltui/button.lua b/src/ltui/button.lua
index 8c2492e..077b469 100644
--- a/src/ltui/button.lua
+++ b/src/ltui/button.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -54,10 +54,10 @@ function button:on_draw(transparent)
     -- strip text string
     local str = self:text()
     if str and #str > 0 then
-        str = string.sub(str, 1, self:width()) 
+        str = string.sub(str, 1, self:width())
     end
     if not str or #str == 0 then
-        return 
+        return
     end
 
     -- get the text attribute value
@@ -77,7 +77,7 @@ function button:on_event(e)
 
     -- selected?
     if not self:state("selected") then
-        return 
+        return
     end
 
     -- enter this button?
diff --git a/src/ltui/canvas.lua b/src/ltui/canvas.lua
index 9857a2d..6c02e3b 100644
--- a/src/ltui/canvas.lua
+++ b/src/ltui/canvas.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -84,7 +84,7 @@ end
 
 -- put character to canvas
 function canvas:putchar(ch, n, vertical)
-    
+
     -- acs character?
     if type(ch) == "string" and #ch > 1 then
         ch = curses.acs(ch)
@@ -111,19 +111,19 @@ end
 
 -- put a string to canvas
 function canvas:putstr(str)
-    self._window:addstr(str) 
+    self._window:addstr(str)
     return self
 end
 
 -- put strings to canvas
 function canvas:putstrs(strs, startline)
-    
+
     -- draw strings
     local sy, sx = self._window:getyx()
     local ey, _ = self._window:getmaxyx()
     for idx = startline or 1, #strs do
         local _, y = self:pos()
-        self._window:addstr(strs[idx]) 
+        self._window:addstr(strs[idx])
         if y + 1 < ey and idx < #strs then
             self:move(sx, y + 1)
         else
diff --git a/src/ltui/choicebox.lua b/src/ltui/choicebox.lua
index 3a52353..82ef7bd 100644
--- a/src/ltui/choicebox.lua
+++ b/src/ltui/choicebox.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -44,7 +44,7 @@ end
 
 -- on event
 function choicebox:on_event(e)
- 
+
     -- select config
     if e.type == event.ev_keyboard then
         if e.key_name == "Down" then
@@ -58,7 +58,7 @@ function choicebox:on_event(e)
     elseif e.type == event.ev_command and e.command == "cm_enter" then
         self:_do_select()
         return true
-    end   
+    end
 end
 
 -- load values
@@ -101,7 +101,7 @@ function choicebox:_do_select()
 
     -- get the current item
     local item = self:current()
-    
+
     -- get the current index
     local index = item:extra("index")
 
diff --git a/src/ltui/choicedialog.lua b/src/ltui/choicedialog.lua
index 00b3662..7aaea22 100644
--- a/src/ltui/choicedialog.lua
+++ b/src/ltui/choicedialog.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -41,11 +41,11 @@ function choicedialog:init(name, bounds, title)
     self:text():text_set("Use the arrow keys to navigate this window or press the hotkey of the item you wish to select followed by the <SPACEBAR>. Press <?> for additional information about this")
 
     -- init buttons
-    self:button_add("select", "< Select >", function (v, e) 
-        self:choicebox():on_event(event.command {"cm_enter"}) 
+    self:button_add("select", "< Select >", function (v, e)
+        self:choicebox():on_event(event.command {"cm_enter"})
         self:quit()
     end)
-    self:button_add("cancel", "< Cancel >", function (v, e) 
+    self:button_add("cancel", "< Cancel >", function (v, e)
         self:quit()
     end)
     self:buttons():select(self:button("select"))
@@ -82,7 +82,7 @@ function choicedialog:on_event(e)
             return self:choicebox():on_event(e)
         end
     end
-    return boxdialog.on_event(self, e) 
+    return boxdialog.on_event(self, e)
 end
 
 -- return module
diff --git a/src/ltui/curses.lua b/src/ltui/curses.lua
index d2511c6..bafa0d3 100644
--- a/src/ltui/curses.lua
+++ b/src/ltui/curses.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -138,7 +138,7 @@ function curses.calc_attr(attrs)
         local set = {}
         local fg = nil
         local bg = nil
-        for _, a in ipairs(attrs) do 
+        for _, a in ipairs(attrs) do
             if not set[a] and a then
                 set[a] = true
                 if type(a) == "number" then
@@ -180,7 +180,7 @@ function curses.color_pair(fg, bg)
 
     -- no colors?
     if not curses.has_colors() then
-        return 0 
+        return 0
     end
 
     -- update the colors count
diff --git a/src/ltui/desktop.lua b/src/ltui/desktop.lua
index 5c261cc..88d8058 100644
--- a/src/ltui/desktop.lua
+++ b/src/ltui/desktop.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
diff --git a/src/ltui/dialog.lua b/src/ltui/dialog.lua
index 991e241..af0e7e4 100644
--- a/src/ltui/dialog.lua
+++ b/src/ltui/dialog.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -31,11 +31,11 @@ local curses = require("ltui/curses")
 
 -- define module
 local dialog = dialog or window()
-    
--- update the position of all buttons 
+
+-- update the position of all buttons
 function dialog:_update_buttons_layout()
 
-    -- update the position of all buttons 
+    -- update the position of all buttons
     local index = 1
     local width = self:buttons():width()
     local count = self:buttons():count()
@@ -87,7 +87,7 @@ function dialog:button_add(name, text, command)
     -- insert button
     self:buttons():insert(btn)
 
-    -- update the position of all buttons 
+    -- update the position of all buttons
     self:_update_buttons_layout()
 
     -- invalidate
diff --git a/src/ltui/event.lua b/src/ltui/event.lua
index f98d43d..91fe658 100644
--- a/src/ltui/event.lua
+++ b/src/ltui/event.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
diff --git a/src/ltui/inputdialog.lua b/src/ltui/inputdialog.lua
index f7917fb..1e055aa 100644
--- a/src/ltui/inputdialog.lua
+++ b/src/ltui/inputdialog.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
diff --git a/src/ltui/label.lua b/src/ltui/label.lua
index 711df82..c2efef1 100644
--- a/src/ltui/label.lua
+++ b/src/ltui/label.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -68,7 +68,7 @@ function label:text_set(text)
     -- set text
     text = text or ""
     local changed = self._TEXT ~= text
-    self._TEXT = text 
+    self._TEXT = text
 
     -- do action
     if changed then
@@ -94,7 +94,7 @@ function label:textattr_val()
     -- get text attribute
     local textattr = self:textattr()
     if not textattr then
-        return 
+        return
     end
 
     -- no text background? use view's background
@@ -117,7 +117,7 @@ end
 
 -- split text by width
 function label:splitext(text, width)
-    
+
     -- get width
     width = width or self:width()
 
diff --git a/src/ltui/mconfdialog.lua b/src/ltui/mconfdialog.lua
index 150ce0b..4954812 100644
--- a/src/ltui/mconfdialog.lua
+++ b/src/ltui/mconfdialog.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -42,7 +42,7 @@ function mconfdialog:init(name, bounds, title)
     boxdialog.init(self, name, bounds, title)
 
     -- init text
-    self:text():text_set([[Arrow keys navigate the menu. <Enter> selects submenus ---> (or empty submenus ----). 
+    self:text():text_set([[Arrow keys navigate the menu. <Enter> selects submenus ---> (or empty submenus ----).
 Pressing <Y> includes, <N> excludes. Enter <Esc> or <Back> to go back, <?> for Help, </> for Search. Legend: [*] built-in  [ ] excluded
 ]])
 
@@ -50,7 +50,7 @@ Pressing <Y> includes, <N> excludes. Enter <Esc> or <Back> to go back, <?> for H
     self:button_add("select", "< Select >", function (v, e) self:menuconf():on_event(event.command {"cm_enter"}) end)
     self:button_add("back", "< Back >", function (v, e) self:menuconf():on_event(event.command {"cm_back"}) end)
     self:button_add("exit", "< Exit >", function (v, e) self:quit() end)
-    self:button_add("help", "< Help >", function (v, e) self:show_help() end) 
+    self:button_add("help", "< Help >", function (v, e) self:show_help() end)
     self:button_add("save", "< Save >", function (v, e) self:action_on(action.ac_on_save) end)
     self:buttons():select(self:button("select"))
 
@@ -144,7 +144,7 @@ function mconfdialog:inputdialog()
         dialog_input:background_set(self:frame():background())
         dialog_input:frame():background_set("cyan")
         dialog_input:textedit():option_set("multiline", false)
-        dialog_input:button_add("ok", "< Ok >", function (v) 
+        dialog_input:button_add("ok", "< Ok >", function (v)
             local config = dialog_input:extra("config")
             if config.kind == "string" then
                 config.value = dialog_input:textedit():text()
@@ -154,9 +154,9 @@ function mconfdialog:inputdialog()
                     config.value = value
                 end
             end
-            dialog_input:quit() 
+            dialog_input:quit()
         end)
-        dialog_input:button_add("cancel", "< Cancel >", function (v) 
+        dialog_input:button_add("cancel", "< Cancel >", function (v)
             dialog_input:quit()
         end)
         dialog_input:button_select("ok")
@@ -185,7 +185,7 @@ function mconfdialog:searchdialog()
         dialog_search:frame():background_set("cyan")
         dialog_search:textedit():option_set("multiline", false)
         dialog_search:text():text_set("Enter (sub)string or lua pattern string to search for configuration")
-        dialog_search:button_add("ok", "< Ok >", function (v) 
+        dialog_search:button_add("ok", "< Ok >", function (v)
             local configs = self:search(self:configs(), dialog_search:textedit():text())
             local results = "Search('" .. dialog_search:textedit():text() .. "') results:"
             for _, config in ipairs(configs) do
@@ -205,9 +205,9 @@ function mconfdialog:searchdialog()
                 results = results .. "\n"
             end
             self:show_result(results)
-            dialog_search:quit() 
+            dialog_search:quit()
         end)
-        dialog_search:button_add("cancel", "< Cancel >", function (v) 
+        dialog_search:button_add("cancel", "< Cancel >", function (v)
             dialog_search:quit()
         end)
         dialog_search:button_select("ok")
@@ -237,7 +237,7 @@ function mconfdialog:show_help()
 
         -- get the current config item
         local item = self:menuconf():current()
-        
+
         -- get the current config
         local config = item:extra("config")
 
@@ -307,7 +307,7 @@ function mconfdialog:on_event(e)
             return true
         end
     end
-    return boxdialog.on_event(self, e) 
+    return boxdialog.on_event(self, e)
 end
 
 -- on resize
diff --git a/src/ltui/menubar.lua b/src/ltui/menubar.lua
index d76451e..2c886c3 100644
--- a/src/ltui/menubar.lua
+++ b/src/ltui/menubar.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
diff --git a/src/ltui/menuconf.lua b/src/ltui/menuconf.lua
index 9131be0..24ba4dc 100644
--- a/src/ltui/menuconf.lua
+++ b/src/ltui/menuconf.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -44,7 +44,7 @@ end
 
 -- on event
 function menuconf:on_event(e)
- 
+
     -- select config
     local back = false
     if e.type == event.ev_keyboard then
@@ -71,7 +71,7 @@ function menuconf:on_event(e)
         elseif e.command == "cm_back" then
             back = true
         end
-    end  
+    end
 
     -- back?
     if back then
@@ -135,19 +135,19 @@ function menuconf:_do_select()
 
     -- get the current item
     local item = self:current()
-    
+
     -- get the current config
     local config = item:extra("config")
 
-    -- clear new state    
+    -- clear new state
     config.new = false
 
     -- do action: on selected
     if self:action_on(action.ac_on_selected, config) then
-        return 
+        return
     end
 
-    -- select the boolean config 
+    -- select the boolean config
     if config.kind == "boolean" then
         config.value = not config.value
     -- show sub-menu configs
@@ -163,14 +163,14 @@ function menuconf:_do_include(enabled)
 
     -- get the current item
     local item = self:current()
-    
+
     -- get the current config
     local config = item:extra("config")
 
-    -- clear new state    
+    -- clear new state
     config.new = false
 
-    -- select the boolean config 
+    -- select the boolean config
     if config.kind == "boolean" then
         config.value = enabled
     end
@@ -200,7 +200,7 @@ end
 -- menu config
 --  - {name = "...", kind = "menu", description = "menu config item", configs = {...}}
 --
-local config = config or object{new = true, 
+local config = config or object{new = true,
                                 __index = function (tbl, key)
                                     if key == "value" then
                                         local val = rawget(tbl, "_value")
@@ -222,7 +222,7 @@ local config = config or object{new = true,
                                             v:text_set(tostring(tbl))
                                         end
                                     end
-                                end} 
+                                end}
 
 -- the prompt info
 function config:prompt()
@@ -243,12 +243,12 @@ function config:__tostring()
 
     -- get value
     local value = self.value
-    
+
     -- update text
     if self.kind == "boolean" or (not self.kind and type(value) == "boolean") then -- boolean config?
         text = (value and "[*] " or "[ ] ") .. text
     elseif self.kind == "number" or (not self.kind and type(value) == "number") then -- number config?
-        text = "    " .. text .. " (" .. tostring(value or 0) .. ")" 
+        text = "    " .. text .. " (" .. tostring(value or 0) .. ")"
     elseif self.kind == "string" or (not self.kind and type(value) == "string") then -- string config?
         text = "    " .. text .. " (" .. tostring(value or "") .. ")"
     elseif self.kind == "choice" then -- choice config?
diff --git a/src/ltui/object.lua b/src/ltui/object.lua
index 48c2f6a..43363c8 100644
--- a/src/ltui/object.lua
+++ b/src/ltui/object.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -76,7 +76,7 @@ local object = { _init = {} }
 setmetatable (object, object)
 
 -- object constructor
---   
+--
 -- @param initial values for fields in
 --
 -- @return new object
diff --git a/src/ltui/panel.lua b/src/ltui/panel.lua
index 5edbaa5..30b549a 100644
--- a/src/ltui/panel.lua
+++ b/src/ltui/panel.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -197,8 +197,8 @@ function panel:select(v)
 
     -- get the current selected view
     local current = self:current()
-    if v == current then 
-        return 
+    if v == current then
+        return
     end
 
     -- undo the previous selected view
@@ -233,7 +233,7 @@ function panel:select_next(start, reset)
 
     -- is empty?
     if self:empty() then
-        return 
+        return
     end
 
     -- reset?
@@ -259,7 +259,7 @@ function panel:select_prev(start)
 
     -- is empty?
     if self:empty() then
-        return 
+        return
     end
 
     -- reset?
@@ -282,10 +282,10 @@ end
 
 -- on event
 function panel:on_event(e)
- 
+
     -- select view?
     if e.type == event.ev_keyboard then
-        -- @note we also use '-' to switch them on termux without right/left and 
+        -- @note we also use '-' to switch them on termux without right/left and
         -- we cannot use tab, because we still need swith views on windows. e.g. inputdialog
         -- @see https://github.com/tboox/ltui/issues/11
         if e.key_name == "Right" or e.key_name == "-" then
@@ -293,7 +293,7 @@ function panel:on_event(e)
         elseif e.key_name == "Left" then
             return self:select_prev()
         end
-    end   
+    end
 end
 
 -- set state
@@ -305,7 +305,7 @@ function panel:state_set(name, enable)
     return self
 end
 
--- draw panel 
+-- draw panel
 function panel:on_draw(transparent)
 
     -- redraw panel?
@@ -327,7 +327,7 @@ function panel:on_draw(transparent)
     end
 end
 
--- resize panel 
+-- resize panel
 function panel:on_resize()
 
     -- resize panel
@@ -347,7 +347,7 @@ function panel:on_refresh()
 
     -- need not refresh? do not refresh it
     if not self:state("refresh") or not self:state("visible") then
-        return 
+        return
     end
 
     -- refresh all child views
@@ -373,17 +373,17 @@ end
 -- tostring(panel, level)
 function panel:_tostring(level)
     local str = ""
-    if self.views then  
+    if self.views then
         str = str .. string.format("<%s %s>", self:name(), tostring(self:bounds()))
         if not self:empty() then
             str = str .. "\n"
         end
-        for v in self:views() do  
+        for v in self:views() do
             for l = 1, level do
                 str = str .. "    "
             end
             str = str .. panel._tostring(v, level + 1) .. "\n"
-        end  
+        end
     else
         str = tostring(self)
     end
diff --git a/src/ltui/point.lua b/src/ltui/point.lua
index bc76638..efd6cef 100644
--- a/src/ltui/point.lua
+++ b/src/ltui/point.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
diff --git a/src/ltui/program.lua b/src/ltui/program.lua
index 7d0d889..72c148f 100644
--- a/src/ltui/program.lua
+++ b/src/ltui/program.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -58,8 +58,8 @@ function program:init(name, argv)
     curses.map_keyboard(true)
 
     -- init colors
-    if (curses.has_colors()) then 
-        curses.start_color() 
+    if (curses.has_colors()) then
+        curses.start_color()
     end
 
     -- disable main window cursor
@@ -108,7 +108,7 @@ function program:main_window()
     -- init main window if not exists
     local main_window = self._MAIN_WINDOW
     if not main_window then
-        
+
         -- init main window
         main_window = curses.init()
         assert(main_window, "cannot init main window!")
@@ -175,7 +175,7 @@ function program:on_event(e)
             return true
         -- refresh?
         elseif e.key_name == "Refresh" then
-            self:invalidate() 
+            self:invalidate()
             return true
         -- ctrl+c? quit program
         elseif e.key_name == "CtrlC" then
@@ -191,7 +191,7 @@ end
 
 -- put an event to view
 function program:put_event(e)
-    
+
     -- init event queue
     self._EVENT_QUEUE = self._EVENT_QUEUE or {}
 
@@ -365,7 +365,7 @@ function program:_input_key()
 
     -- get input character
     local ch = main_window:getch()
-    if not ch then 
+    if not ch then
         return
     end
 
@@ -397,17 +397,17 @@ function program:_input_key()
                 end
 
                 -- wait some time, 50ms
-                curses.napms(50) 
+                curses.napms(50)
                 t = t + 50
             end
 
             -- nothing was typed... return Esc
-            if not ch then 
-                return 27, "Esc", false 
+            if not ch then
+                return 27, "Esc", false
             end
         end
-        if ch > 96 and ch < 123 then 
-            ch = ch - 32 
+        if ch > 96 and ch < 123 then
+            ch = ch - 32
         end
     end
 
diff --git a/src/ltui/rect.lua b/src/ltui/rect.lua
index 56a2df1..53b69ad 100644
--- a/src/ltui/rect.lua
+++ b/src/ltui/rect.lua
@@ -12,7 +12,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
diff --git a/src/ltui/statusbar.lua b/src/ltui/statusbar.lua
index 5faf5ea..3c10104 100644
--- a/src/ltui/statusbar.lua
+++ b/src/ltui/statusbar.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
diff --git a/src/ltui/textarea.lua b/src/ltui/textarea.lua
index f06b647..8fb5eb0 100644
--- a/src/ltui/textarea.lua
+++ b/src/ltui/textarea.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -88,7 +88,7 @@ function textarea:scroll(lines)
             self._STARTLINE = 0
         end
         if self._STARTLINE > self._LINECOUNT - self:height() then
-            self._STARTLINE = self._LINECOUNT - self:height() 
+            self._STARTLINE = self._LINECOUNT - self:height()
         end
         self:invalidate()
     end
@@ -97,7 +97,7 @@ end
 -- scroll to end
 function textarea:scroll_to_end()
     if self._LINECOUNT > self:height() then
-        self._STARTLINE = self._LINECOUNT - self:height() 
+        self._STARTLINE = self._LINECOUNT - self:height()
         self:invalidate()
     end
 end
diff --git a/src/ltui/textdialog.lua b/src/ltui/textdialog.lua
index f655450..fa2eec4 100644
--- a/src/ltui/textdialog.lua
+++ b/src/ltui/textdialog.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -58,7 +58,7 @@ end
 
 -- on event
 function textdialog:on_event(e)
-    
+
     -- pass event to dialog
     if dialog.on_event(self, e) then
         return true
diff --git a/src/ltui/textedit.lua b/src/ltui/textedit.lua
index a6a3624..223f447 100644
--- a/src/ltui/textedit.lua
+++ b/src/ltui/textedit.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -97,7 +97,7 @@ function textedit:on_event(e)
     end
 
     -- do textarea event
-    return textarea.on_event(self, e) 
+    return textarea.on_event(self, e)
 end
 
 -- return module
diff --git a/src/ltui/view.lua b/src/ltui/view.lua
index c8390db..12c498d 100644
--- a/src/ltui/view.lua
+++ b/src/ltui/view.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -60,7 +60,7 @@ function view:init(name, bounds)
     state.block_cursor   = false     -- block cursor
     state.selected       = false     -- is selected?
     state.focused        = false     -- is focused?
-    state.redraw         = true      -- need redraw 
+    state.redraw         = true      -- need redraw
     state.on_refresh     = true      -- need refresh
     state.on_resize      = true      -- need resize
     self._STATE          = state
@@ -112,7 +112,7 @@ end
 -- set window bounds
 function view:bounds_set(bounds)
     if bounds and self:bounds() ~= bounds then
-        self._BOUNDS = bounds() 
+        self._BOUNDS = bounds()
         self:invalidate(true)
     end
 end
@@ -142,7 +142,7 @@ function view:parent_set(parent)
     self._PARENT = parent
 end
 
--- get the application 
+-- get the application
 function view:application()
     if not self._APPLICATION then
         local app = self
@@ -236,13 +236,13 @@ function view:on_resize()
 
     -- clear mark
     self:state_set("resize", false)
-    
+
     -- do action
     self:action_on(action.ac_on_resized)
 end
 
 -- show view?
--- 
+--
 -- .e.g
 -- v:show(false)
 -- v:show(true, {focused = true})
@@ -269,7 +269,7 @@ function view:invalidate(bounds)
 end
 
 -- on event (abstract)
--- 
+--
 -- @return true: done and break dispatching, false/nil: continous to dispatch to other views
 --
 function view:on_event(e)
@@ -326,7 +326,7 @@ function view:option_set(name, enable)
     -- state is not changed?
     enable = enable or false
     if self:option(name) == enable then
-        return 
+        return
     end
 
     -- set option
@@ -482,7 +482,7 @@ function view:_mark_refresh()
         self:state_set("refresh", true)
     end
 
-    -- need refresh it's parent view 
+    -- need refresh it's parent view
     if self:parent() then
         self:parent():_mark_refresh()
     end
diff --git a/src/ltui/window.lua b/src/ltui/window.lua
index 761a9df..c0f3a24 100644
--- a/src/ltui/window.lua
+++ b/src/ltui/window.lua
@@ -11,7 +11,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -97,12 +97,12 @@ function window:title()
     return self._TITLE
 end
 
--- get shadow 
+-- get shadow
 function window:shadow()
     return self._SHADOW
 end
 
--- get border 
+-- get border
 function window:border()
     if not self._BORDER then
         self._BORDER = border:new("window.border", self:frame():bounds())
@@ -118,7 +118,7 @@ function window:on_event(e)
         if e.key_name == "Tab" then
             return self:panel():select_next()
         end
-    end   
+    end
 end
 
 -- on resize
diff --git a/tests/desktop.lua b/tests/desktop.lua
index cfcdfb3..7ac0d00 100755
--- a/tests/desktop.lua
+++ b/tests/desktop.lua
@@ -15,7 +15,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -37,7 +37,7 @@ local demo = application()
 -- init demo
 function demo:init()
 
-    -- init name 
+    -- init name
     application.init(self, "demo")
 
     -- show desktop, menubar and statusbar
diff --git a/tests/dialog.lua b/tests/dialog.lua
index f540402..823ca00 100644
--- a/tests/dialog.lua
+++ b/tests/dialog.lua
@@ -15,7 +15,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -40,7 +40,7 @@ local demo = application()
 -- init demo
 function demo:init()
 
-    -- init name 
+    -- init name
     application.init(self, "demo")
 
     -- init background
@@ -99,9 +99,9 @@ function demo:dialog_input()
         dialog_input:frame():background_set("cyan")
         dialog_input:text():text_set("please input text:"):textattr_set("red")
         dialog_input:button_add("no", "< No >", function (v) dialog_input:show(false) end)
-        dialog_input:button_add("yes", "< Yes >", function (v) 
+        dialog_input:button_add("yes", "< Yes >", function (v)
                                                       self:dialog_main():text():text_set(dialog_input:textedit():text())
-                                                      dialog_input:show(false) 
+                                                      dialog_input:show(false)
                                                   end)
         dialog_input:show(false)
         self._DIALOG_INPUT = dialog_input
@@ -123,7 +123,7 @@ function demo:dialog_tips()
     return dialog_tips
 end
 
--- on resize  
+-- on resize
 function demo:on_resize()
     self:dialog_main():bounds_set(rect {1, 1, self:width() - 1, self:height() - 1})
     self:dialog_help():bounds_set(rect {1, 1, self:width() - 1, self:height() - 1})
diff --git a/tests/events.lua b/tests/events.lua
index 55b616f..f67b393 100644
--- a/tests/events.lua
+++ b/tests/events.lua
@@ -15,7 +15,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2020, TBOOX Open Source Group.
 --
 -- @author      Lael N. Santos
@@ -37,7 +37,7 @@ local demo = application()
 -- init demo
 function demo:init()
 
-    -- init name 
+    -- init name
     application.init(self, "demo")
 
     -- init background
@@ -74,7 +74,7 @@ end
 
 -- on event
 function demo:on_event(e)
-    if e.type < event.ev_max then 
+    if e.type < event.ev_max then
         self:teste():text_set('type: ' ..
             tostring(e.type) ..
             '; name: ' ..
diff --git a/tests/inputdialog.lua b/tests/inputdialog.lua
index b743a35..7caf276 100644
--- a/tests/inputdialog.lua
+++ b/tests/inputdialog.lua
@@ -15,7 +15,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -38,7 +38,7 @@ local demo = application()
 -- init demo
 function demo:init()
 
-    -- init name 
+    -- init name
     application.init(self, "demo")
 
     -- init background
diff --git a/tests/load.lua b/tests/load.lua
index 288792a..422216a 100755
--- a/tests/load.lua
+++ b/tests/load.lua
@@ -1,3 +1,3 @@
--- init load directories 
+-- init load directories
 package.path  = package.path .. ';./src/?.lua'
 package.cpath = package.cpath .. ';./build/ltui.dll;./build/libltui.so;./build/libltui.dylib'
diff --git a/tests/mconfdialog.lua b/tests/mconfdialog.lua
index e781dd5..031f535 100644
--- a/tests/mconfdialog.lua
+++ b/tests/mconfdialog.lua
@@ -15,7 +15,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -40,7 +40,7 @@ local demo = application()
 -- init demo
 function demo:init()
 
-    -- init name 
+    -- init name
     application.init(self, "demo")
 
     -- init background
@@ -82,7 +82,7 @@ function demo:dialog_mconf()
     if not dialog_mconf then
         dialog_mconf = mconfdialog:new("mconfdialog.main", rect{1, 1, self:width() - 1, self:height() - 1}, "menu config")
         dialog_mconf:action_set(action.ac_on_exit, function (v) self:quit() end)
-        dialog_mconf:action_set(action.ac_on_save, function (v) 
+        dialog_mconf:action_set(action.ac_on_save, function (v)
             -- TODO save configs
             dialog_mconf:quit()
         end)
diff --git a/tests/window.lua b/tests/window.lua
index 9e246fa..14eefee 100644
--- a/tests/window.lua
+++ b/tests/window.lua
@@ -15,7 +15,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -36,7 +36,7 @@ local demo = application()
 -- init demo
 function demo:init()
 
-    -- init name 
+    -- init name
     application.init(self, "demo")
 
     -- init background
diff --git a/xmake.lua b/xmake.lua
index 1da7b55..29ffda9 100644
--- a/xmake.lua
+++ b/xmake.lua
@@ -29,8 +29,8 @@ set_strip("all")
 add_cxflags("-fomit-frame-pointer")
 
 -- for the windows platform (msvc)
-if is_plat("windows") then 
-    add_cxflags("-MT") 
+if is_plat("windows") then
+    add_cxflags("-MT")
     add_defines("_CRT_SECURE_NO_WARNINGS")
     add_shflags("-nodefaultlib:msvcrt.lib")
     add_links("kernel32", "user32", "gdi32", "advapi32")
@@ -106,7 +106,7 @@ target("ltui")
     -- add lua and do not link it on linux and macos
     local lualinks = nil
     if is_plat("macosx", "linux", "bsd") then
-        lualinks = {} 
+        lualinks = {}
     end
     if has_config("luajit") then
         add_defines("LUAJIT")
@@ -114,8 +114,8 @@ target("ltui")
     else
         add_packages("lua", {links = lualinks})
     end
-  
-    -- add curses 
+
+    -- add curses
     if is_plat("windows") then
         add_defines("PDCURSES")
         add_includedirs("src/core/pdcurses")