When using Ultratoolbar 8.1

ultraToolbarsManager1.ToolbarSettings.AllowCustomize = DefaultableBoolean.False;

how to reproduce:

1. add ultratoolbarmanager and some toolbars
2. add some buttons on the toolbars
3. add several buttons on the toolbar, so their total width will be more than all toolbars widths
4. in windows XP, make sure the "window content is refreshed when window is resized" option is turned ON
5. resize the form and see some buttons disappearing on the toolbar

ps: submitted demo code to bug reporting system