Improve widgets sample UI consistency.

Ensure that the various attributes (colours, font, border, ...) are preserved
when a widget is recreated or the current page is changed. This is more
convenient and also avoids discrepancies between the state of the menu items
and the actual state of the widget.

Closes #16576.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@78332 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

samples/widgets/combobox.cpp

@@ -407,7 +407,7 @@ void ComboboxWidgetsPage::Reset()
 
 void ComboboxWidgetsPage::CreateCombo()
 {
-    int flags = ms_defaultFlags;
+    int flags = GetAttrs().m_defaultFlags;
 
     if ( m_chkSort->GetValue() )
         flags |= wxCB_SORT;