Single-window mode crashes
Gajim constantly crashes as soon as I enable the single-window mode, with the following output:
$ ./launch.py
14/10/2017 18:15:28 (W) gajim.plugin_system Plugin plugin_installer not loaded, plugin incompatible with current version of gajim: 0.16.11.1 > 0.16.9
14/10/2017 18:15:28 (W) gajim.plugin_system Plugin gnome_session_manager not loaded, plugin incompatible with current version of gajim: 0.16.11.1 > 0.16.9
(gajim:9479): Gtk-WARNING **: Don't know color ''
(gajim:9479): Gtk-CRITICAL **: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GtkScrollbar
(gajim:9479): Gtk-WARNING **: Don't know color ''
(gajim:9479): Gtk-WARNING **: Don't know color ''
(gajim:9479): Gtk-WARNING **: Don't know color ''
(gajim:9479): Gtk-WARNING **: Don't know color ''
(gajim:9479): Gtk-WARNING **: Don't know color ''
(gajim:9479): Gtk-CRITICAL **: _gtk_rbtree_reorder: assertion 'tree->root->count == length' failed
(gajim:9479): Gtk-CRITICAL **: _gtk_rbtree_reorder: assertion 'tree->root->count == length' failed
(gajim:9479): Gtk-CRITICAL **: _gtk_rbtree_reorder: assertion 'tree->root->count == length' failed
(gajim:9479): Gtk-CRITICAL **: _gtk_rbtree_reorder: assertion 'tree->root->count == length' failed
**
Gtk:ERROR:../../../../gtk/gtkrbtree.c:471:_gtk_rbtree_insert_after: assertion failed: (_gtk_rbtree_is_nil (tree->root))
Abandon (core dumped)