diff --git a/src/ltui/base/hashset.lua b/src/ltui/base/hashset.lua
deleted file mode 100644
index ce4d92e..0000000
--- a/src/ltui/base/hashset.lua
+++ /dev/null
@@ -1,136 +0,0 @@
-
---!A cross-platform terminal ui library based on Lua
---
--- Licensed under the Apache License, Version 2.0 (the "License");
--- you may not use this file except in compliance with the License.
--- You may obtain a copy of the License at
---
---     http://www.apache.org/licenses/LICENSE-2.0
---
--- Unless required by applicable law or agreed to in writing, software
--- distributed under the License is distributed on an "AS IS" BASIS,
--- 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      OpportunityLiu
--- @file        hashset.lua
---
-
--- define module
-local hashset      = hashset or {}
-local hashset_impl = hashset.__index or {}
-
--- load modules
-local table      = require("base/table")
-
--- representaion for nil key
-hashset._NIL = setmetatable({}, {__tostring = function() return "symbol(nil)" end })
-
-function hashset._to_key(key)
-    if key == nil then
-        key = hashset._NIL
-    end
-    return key
-end
-
--- make a new hashset
-function hashset.new()
-    return setmetatable({ _DATA = {}, _SIZE = 0 }, hashset)
-end
-
--- construct from list of items
-function hashset.of(...)
-    local result = hashset.new()
-    local data = table.pack(...)
-    for i = 1, data.n do
-        result:insert(data[i])
-    end
-    return result
-end
-
--- construct from an array
-function hashset.from(array)
-    assert(array)
-    return hashset.of(table.unpack(array))
-end
-
--- check value is in hashset
-function hashset_impl:has(value)
-    value = hashset._to_key(value)
-    return self._DATA[value] or false
-end
-
--- insert value to hashset, returns false if value has already in the hashset
-function hashset_impl:insert(value)
-    value = hashset._to_key(value)
-    local result = not (self._DATA[value] or false)
-    if result then
-        self._DATA[value] = true
-        self._SIZE = self._SIZE + 1
-    end
-    return result
-end
-
--- remove value from hashset, returns false if value is not in the hashset
-function hashset_impl:remove(value)
-    value = hashset._to_key(value)
-    local result = self._DATA[value] or false
-    if result then
-        self._DATA[value] = nil
-        self._SIZE = self._SIZE - 1
-    end
-    return result
-end
-
--- convert hashset to an array, nil in the set will be ignored
-function hashset_impl:to_array()
-    local result = {}
-    for k, _ in pairs(self._DATA) do
-        if k ~= hashset._NIL then
-            table.insert(result, k)
-        end
-    end
-    return result
-end
-
--- iterate keys of hashtable
--- for _, key in instance:keys() do ... end
-function hashset_impl:keys()
-    return function (table, key)
-        local k, _ = next(table._DATA, key)
-        if k == hashset._NIL then
-            return k, nil
-        else
-            return k, k
-        end
-    end, self, nil
-end
-
--- get size of hashset
-function hashset_impl:size()
-    return self._SIZE
-end
-
--- is empty?
-function hashset_impl:empty()
-    return self:size() == 0
-end
-
--- get data of hashset
-function hashset_impl:data()
-    return self._DATA
-end
-
--- clear hashset
-function hashset_impl:clear()
-    self._DATA = {}
-    self._SIZE = 0
-end
-
--- return module
-hashset.__index = hashset_impl
-return hashset
diff --git a/src/ltui/base/table.lua b/src/ltui/base/table.lua
index d71409f..504c058 100644
--- a/src/ltui/base/table.lua
+++ b/src/ltui/base/table.lua
@@ -61,110 +61,6 @@ function table.join2(self, ...)
     return self
 end
 
--- append all objects to array
-function table.append(array, ...)
-    for _, value in ipairs({...}) do
-        table.insert(array, value)
-    end
-    return array
-end
-
--- copy the table to self
-function table.copy(copied)
-
-    -- init it
-    copied = copied or {}
-
-    -- copy it
-    local result = {}
-    for k, v in pairs(table.wrap(copied)) do
-        result[k] = v
-    end
-
-    -- ok
-    return result
-end
-
--- copy the table to self
-function table.copy2(self, copied)
-
-    -- check
-    assert(self)
-
-    -- init it
-    copied = copied or {}
-
-    -- clear self first
-    table.clear(self)
-
-    -- copy it
-    for k, v in pairs(table.wrap(copied)) do
-        self[k] = v
-    end
-
-end
-
--- inherit interfaces and create a new instance
-function table.inherit(...)
-
-    -- init instance
-    local classes = {...}
-    local instance = {}
-    local metainfo = {}
-    for _, clasz in ipairs(classes) do
-        for k, v in pairs(clasz) do
-            if type(v) == "function" then
-                if k:startswith("__") then
-                    if metainfo[k] == nil then
-                        metainfo[k] = v
-                    end
-                else
-                    if instance[k] == nil then
-                        instance[k] = v
-                    else
-                        instance["_super_" .. k] = v
-                    end
-                end
-            end
-        end
-    end
-    setmetatable(instance, metainfo)
-
-    -- ok?
-    return instance
-end
-
--- inherit interfaces from the given class
-function table.inherit2(self, ...)
-
-    -- check
-    assert(self)
-
-    -- init instance
-    local classes = {...}
-    local metainfo = getmetatable(self) or {}
-    for _, clasz in ipairs(classes) do
-        for k, v in pairs(clasz) do
-            if type(v) == "function" then
-                if k:startswith("__") then
-                    if metainfo[k] == nil then
-                        metainfo[k] = v
-                    end
-                else
-                    if self[k] == nil then
-                        self[k] = v
-                    else 
-                        self["_super_" .. k] = v
-                    end
-                end
-            end
-        end
-    end
-
-    -- ok?
-    return self
-end
-
 -- slice table array
 function table.slice(self, first, last, step)
 
@@ -186,86 +82,6 @@ function table.is_dictionary(dict)
     return type(dict) == "table" and dict[1] == nil
 end
 
--- dump it with the level
-function table._dump(self, exclude, level)
- 
-    -- dump basic type
-    if type(self) == "string" or type(self) == "boolean" or type(self) == "number" then  
-        io.write(tostring(self))  
-    elseif type(self) == "table" and (getmetatable(self) or {}).__tostring then
-        io.write(tostring(self))  
-    -- dump table
-    elseif type(self) == "table" then  
-
-        -- dump head
-        io.write("\n")  
-        for l = 1, level do
-            io.write("    ")
-        end
-        io.write("{\n")
-
-        -- dump body
-        local i = 0
-        for k, v in pairs(self) do  
-
-            -- exclude some keys
-            if not exclude or type(k) ~= "string" or not k:find(exclude) then
-
-                -- dump spaces and separator
-                for l = 1, level do
-                    io.write("    ")
-                end
-
-                if i == 0 then
-                    io.write("    ")
-                else
-                    io.write(",   ")
-                end
-                
-                -- dump key
-                if type(k) == "string" then
-                    io.write(k, " = ")  
-                end
-
-                -- dump value
-                table._dump(v, exclude, level + 1)  
-
-                -- dump newline
-                io.write("\n")
-                i = i + 1
-            end
-        end  
-
-        -- dump tail
-        for l = 1, level do
-            io.write("    ")
-        end
-        io.write("}\n")  
-    elseif self ~= nil then
-        io.write("<" .. tostring(self) .. ">")
-    else
-        io.write("nil")
-    end
-end
-
--- dump it
-function table.dump(self, exclude, prefix)
-
-    -- dump prefix
-    if prefix then
-        io.write(prefix)
-    end
-  
-    -- dump it
-    table._dump(self, exclude, 0)
-
-    -- end
-    print("")
-
-    -- return it
-    return self
-end
-
 -- unwrap object if be only one
 function table.unwrap(object)
     if type(object) == "table" then
@@ -336,5 +152,82 @@ function table.unique(array, barrier)
     return array
 end
 
+-- pack arguments into a table
+-- polyfill of lua 5.2, @see https://www.lua.org/manual/5.2/manual.html#pdf-table.pack
+function table.pack(...)
+    return { n = select("#", ...), ... }
+end
+
+-- unpack table values
+-- polyfill of lua 5.2, @see https://www.lua.org/manual/5.2/manual.html#pdf-table.unpack
+table.unpack = unpack
+
+-- get keys of a table
+function table.keys(tab)
+
+    assert(tab)
+
+    local keyset = {}
+    local n = 0
+    for k, _ in pairs(tab) do
+        n = n + 1
+        keyset[n] = k
+    end
+    return keyset, n
+end
+
+-- get values of a table
+function table.values(tab)
+
+    assert(tab)
+
+    local valueset = {}
+    local n = 0
+    for _, v in pairs(tab) do
+        n = n + 1
+        valueset[n] = v
+    end
+    return valueset, n
+end
+
+-- map values to a new table
+function table.map(tab, mapper)
+
+    assert(tab)
+    assert(mapper)
+
+    local newtab = {}
+    for k, v in pairs(tab) do
+        newtab[k] = mapper(k, v)
+    end
+    return newtab
+end
+
+-- map values to a new array
+function table.imap(arr, mapper)
+
+    assert(arr)
+    assert(mapper)
+
+    local newarr = {}
+    for k, v in ipairs(arr) do
+        table.insert(newarr, mapper(k, v))
+    end
+    return newarr
+end
+
+-- reverse table values
+function table.reverse(arr)
+
+    assert(arr)
+
+    local revarr = {}
+    local l = #arr
+    for i = 1, l do
+        revarr[i] = arr[l - i + 1]
+    end
+    return revarr
+end
+
 -- return module: table
 return table
diff --git a/src/ltui/boxdialog.lua b/src/ltui/boxdialog.lua
index 8da8dda..2ee8dae 100644
--- a/src/ltui/boxdialog.lua
+++ b/src/ltui/boxdialog.lua
@@ -51,7 +51,7 @@ function boxdialog:init(name, bounds, title)
             local lines = #self:text():splitext(v:text())
             if lines > 0 and lines < self:height() then
                 self._TEXT_EY = lines
-                self:invalidate(true)
+                self:panel():invalidate(true)
                 --[[
                 self:box():bounds().sy = lines
                 self:text():bounds().ey = lines
diff --git a/src/ltui/panel.lua b/src/ltui/panel.lua
index 7d1537a..30270da 100644
--- a/src/ltui/panel.lua
+++ b/src/ltui/panel.lua
@@ -139,15 +139,8 @@ function panel:insert(v, opt)
         self:select(v)
     end
 
-    -- @note we need force to trigger on_resize for this panel for 
-    -- passing on_resize event to this subview if this subview has been resized?
-    local resize = false
-    if v:state("resize") and not self:state("resize") then
-        resize = true
-    end
-
     -- invalidate it
-    self:invalidate(resize)
+    self:invalidate()
 end
 
 -- remove view
diff --git a/src/ltui/program.lua b/src/ltui/program.lua
index c4d5c8b..1ea879e 100644
--- a/src/ltui/program.lua
+++ b/src/ltui/program.lua
@@ -19,12 +19,12 @@
 --
 
 -- load modules
-local log    = require("ltui/base/log")
-local rect   = require("ltui/rect")
-local point  = require("ltui/point")
-local panel  = require("ltui/panel")
-local event  = require("ltui/event")
-local curses = require("ltui/curses")
+local log     = require("ltui/base/log")
+local rect    = require("ltui/rect")
+local point   = require("ltui/point")
+local panel   = require("ltui/panel")
+local event   = require("ltui/event")
+local curses  = require("ltui/curses")
 
 -- define module
 local program = program or panel()
diff --git a/src/ltui/view.lua b/src/ltui/view.lua
index 5d15425..1524bc8 100644
--- a/src/ltui/view.lua
+++ b/src/ltui/view.lua
@@ -442,6 +442,11 @@ function view:_mark_resize()
 
     -- need resize it
     self:state_set("resize", true)
+
+    -- @note we need trigger on_resize() of the root view and pass it to this subview
+    if self:parent() then
+        self:parent():invalidate(true)
+    end
 end
 
 -- need redraw view