Hello there, it is not possible to CTRL+SELECT arranger events.
The previously selected event always gets deselected.
Shift + Click selects mutliples.
Yes it does, as does CTRL+CLICK. The difference is, that by SHIFT+CLICKing you can select all events, but not deselect an already selected one (which CTRL+CLICK is good for). CTRL+CLICK does work everywhere else in Cubase, just not for arranger tracks.