https://bugzilla.redhat.com/show_bug.cgi?id=2013610
--- Comment #3 from Mike FABIAN mfabian@redhat.com --- See also https://github.com/ibus/ibus-m17n/issues/27
The problem in ibus-m17n described there is caused by committing something and then passing a space with "return False". This does not work correctly in XIM and because emacs uses XIM this causes the problem in Emacs.