For those who experience "NextGroup" problems, here is the procedure that make Alt-Shift works for me.
The problem seems to be that "Text Entry" double-detect the Alt-Shift as "NextGroup" key, which is the layout switch shortcut from xkb. The idea is to completely disable xkboptions for layout switching.
1. Install latest PPA packages of gnome-control-center and gnome-settings from above.
2. sudo vi /etc/default/keyboard, comment out everything unless you want to redo everything again.
3. dconf-editor, edit org->gnome->desktop->input-sources, empty "xkb-options". In my turn I have also empty "sources". YMMV.
4. Under System-Settings->Text-Entry, readd layout that might disappeared from the step above, the reassign shortcut as you desired. It should not detect Alt-Shift as "NextGroup" anymore.
5. For those who still doesn't works, try empty value in org->gnome->libgnomekbd->keyboard. I emptied all values including model, layout, and options.
For those who experience "NextGroup" problems, here is the procedure that make Alt-Shift works for me.
The problem seems to be that "Text Entry" double-detect the Alt-Shift as "NextGroup" key, which is the layout switch shortcut from xkb. The idea is to completely disable xkboptions for layout switching.
1. Install latest PPA packages of gnome-control- center and gnome-settings from above. keyboard, comment out everything unless you want to redo everything again. >desktop- >input- sources, empty "xkb-options". In my turn I have also empty "sources". YMMV. Settings- >Text-Entry, readd layout that might disappeared from the step above, the reassign shortcut as you desired. It should not detect Alt-Shift as "NextGroup" anymore. >libgnomekbd- >keyboard. I emptied all values including model, layout, and options.
2. sudo vi /etc/default/
3. dconf-editor, edit org->gnome-
4. Under System-
5. For those who still doesn't works, try empty value in org->gnome-
Hope this helps.