How to reproduce: Open the message composer Select: Spelling -> Options -> [ ] Use both dictionaries Set it to [x] using spacebar. Result: X is locked. You have to use a tty to kill -14 claws-mail The only error message claws-mail puts is (claws-mail:17403): Gtk-CRITICAL **: IA__gtk_widget_event: assertion `WIDGET_REALIZED_FOR_EVENT (widget, event)' failed Experienced using claws-mail 3.9.0 on debian sid with Openbox and claws-mail 3.9.0 with i3wm on Gentoo