On rawhide, ibus is not started automatically when using non-Gnome desktops like KDE or xfce. On Fedora 18, ibus used to be started automatically for KDE and xfce as well. The environment variables QT_IM_MODULE=ibus XMODIFIERS=@im=ibus GTK_IM_MODULE=ibus are set automatically though even for KDE on rawhide.
Created attachment 708472 [details] ~/.cache/imsettings/log ~/.cache/imsettings/log
Maybe it's not an ibus issue.
should be fixed in imsettings-1.6.0-3.fc19.
Works, thank you!