I noticed that xfwm4's plugins use a deprecated GTK widget (and don't rely on any feature of it which is missing in its replacement). Hence the following patch...
Created attachment 651
Use GtkComboBox instead of GtkOptionMenu
Ah, ok thanks! It works also on gtk+-2.6, doesn"t it?
Should do. I see no reason why it shouldn't: there's nothing in the patch which requires GTK+ 2.8 or later.
ok, thanks, it's now in svn trunk.