Comment 6 for bug 1760308

Thanks for fixing this, Sebastien!

When I saw your oneliner in the queue, I did some tests. Without having your ibus-fix in place, I opened gnome-language-selector, selected "none" instead of "IBus", and re-logged in. That disables im-config's variable settings, and only the IM related variables which GNOME sets by default are present:

$ env | grep -E 'XMOD|_IM'
QT_IM_MODULE=ibus
XMODIFIERS=@im=ibus

And it made Ctrl+Shift+U work.

These are the variables with im-config enabled:

$ env | grep -E 'XMOD|_IM'
CLUTTER_IM_MODULE=xim
QT4_IM_MODULE=xim
QT_IM_MODULE=ibus
XMODIFIERS=@im=ibus
GTK_IM_MODULE=ibus

I also tried to just edit ~/.profile and add:

unset GTK_IM_MODULE

That proved to be sufficient to bring Ctrl+Shift+U back.

I'm not able to tell the significance of setting GTK_IM_MODULE to "ibus", but that's what we currently do through im-config, and Ubuntu is the only distro AFAIK which installs im-config by default. So the issue is kind of Ubuntu specific, and now we have an Ubuntu specific ibus-patch.

My first reaction was to try to convince upstream to change their mind. I'm not as sure about that now.