has been destroyed or recreated. On wxMSW, this is done in
~wxToolBar. On wxGTK, in SetToolBar. In wxMac, not at all,
but sending a wxSizeEvent will do it.
+- Need wxRect wxToolBar::GetToolRect(int id) or similar so we can
+ align a popup menu with a toolbar button.
- wxMac font selector dialog is the generic font selector -
horrible.
- No Append(wxArrayString&) for wxChoice and wxComboBox in wxGTK.