diff --git a/kernel/trunk/gui/window.inc b/kernel/trunk/gui/window.inc
index d6312fb9bd..53e922070f 100644
--- a/kernel/trunk/gui/window.inc
+++ b/kernel/trunk/gui/window.inc
@@ -128,6 +128,10 @@ dd  .setSkinUnicode
         cmp     edx, 192
         jnae    @f
         mov     edx, 192 ; max size
+@@:
+        stdcall is_region_userspace, esi, edx    ;
+        jnz     @f                               ;
+        ret                                      ;
 @@:
         mov     edi, common_colours
         mov     ecx, edx