For the past years I have used GTK_IM_MODULE=xim, mostly for the compose key functionality and ~/.XCompose. Unfortunately the latest stable Eclipse release does not work at all using xim: It will run out of SWT handles (see [1, 2]; as it turns out, xim was unsupported by Eclipse for a while before).
It appears that people have been recommending setting GTK_IM_METHOD to xim for compose key functionally in the past, because otherwise GTK would not respect ~/.XCompose. But I assume that this has changed in recent GTK versions as
GTK_IM_MODULE=gtk-im-context-simple evince
allows be to use my compose key. But unfortunately once I set GTK_IM_MODULE to gtk-im-context-simple I can no longer type an underscore using shift+<hypen>.
I have tried to debug the issue by starting evince with --gtk-debug keybindings, which yields the following output:
On keypress ‘hypen’:
Gtk-Message: 00:38:01.808: Looking up keycode = 20, modifiers = 0x0001,
keyval = 95, group = 0, level = 1, consumed_modifiers = 0x6003
On keypress ‘underscore’ (shift+<hypen>):
Gtk-Message: 00:38:01.862: Looking up keycode = 50, modifiers = 0x0001,
keyval = 65505, group = 0, level = 0, consumed_modifiers = 0x6002
Note the “keyval = 65505”. I assume that means that some mapping is off. Unfortunately I do not know how to debug further from here.
Why can I no longer write underscores (and potentially other keysyms) once I use gtk-im-context-simple?
1: https://bugs.eclipse.org/bugs/show_bug.cgi?id=542675#c9
2: https://bugs.eclipse.org/bugs/show_bug.cgi?id=517671