Fix undefined index in mentions due to broken logic

Signed-off-by: emanuele <emanuele45@gmail.com>
Populate menu subbuttons only if the parent exists

Signed-off-by: emanuele <emanuele45@gmail.com>
Re-testing of members mentions was broken... badly

Signed-off-by: emanuele <emanuele45@gmail.com>
Firefox and Chrome have different opinions on white-space:nowrap

Signed-off-by: emanuele <emanuele45@gmail.com>
Merge pull request #1218 from emanuele45/fixins

Fixins