I have this problem in the Gedit searchbox too, in Ubuntu 16.04 / Gedit 3.18.3, and not merely with AltGr-combinations but even with Shift (uppercase) keys. I can also confirm that the same is happening in input fields in certain websites on Firefox.
Gedit gives an error message on stderr every time this happens:
** (gedit:29772): WARNING **: (gedit/gedit-view-frame.c:121):get_iter_at_start_mark: code should not be reached
I have this problem in the Gedit searchbox too, in Ubuntu 16.04 / Gedit 3.18.3, and not merely with AltGr-combinations but even with Shift (uppercase) keys. I can also confirm that the same is happening in input fields in certain websites on Firefox.
Gedit gives an error message on stderr every time this happens: gedit-view- frame.c: 121):get_ iter_at_ start_mark: code should not be reached
** (gedit:29772): WARNING **: (gedit/