https://bugzilla.redhat.com/show_bug.cgi?id=997645
--- Comment #5 from Tom "spot" Callaway tcallawa@redhat.com --- Revisiting this... I tested the perl-GTK2 that was in Fedora 17 (1.241) and it doesn't make a colored button in Fedora 20 and your test code.
So... this is either a behavior that changed in GTK2 between Fedora 17 (2.24.13) and now (2.24.22) or.... something else. Either way, I think the perl-Gtk2 upstream is the place to open this bug.