These packages make use of gtk3 useflag which indicates that there are issues of migration to gtk+:3. Gtk3 and similar useflags should be avoided. Adding to tracker. Please have a look. On top of that, this seems to be missing dependency gtk+:3 completely (even if gtk3 useflag is enabled).
Not a bug. The gtk3 useflag is used as intended here.
(In reply to comment #1) > Not a bug. The gtk3 useflag is used as intended here. The GTK+-3.x version of the program does something different than the GTK+-2.x version? Like write different config files? If not, then this bug should be reopened