make IsEnabled() return false even if the window parent, and not the window itself, is disabled and added IsThisEnabled() implementing the old IsEnabled() behaviour; also significantly simplify the window state management code in all ports by factoring out the common parts in wxWindowBase

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@45031 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/palmos/window.h

@@ -270,9 +270,6 @@ private:
     bool HandleMoving(wxRect& rect);
     bool HandleJoystickEvent(WXUINT msg, int x, int y, WXUINT flags);
 
-    // list of disabled children before last call to our Disable()
-    wxWindowList *m_childrenDisabled;
-
     // number of calls to Freeze() minus number of calls to Thaw()
     unsigned int m_frozenness;