It could be your do not pass list is not setup to block the keys being passed.

For example, if you have CTRL + 3 on your main bound to a spell or a command, it might not be done on your alts. Either rebind their keys or add all combinations to the do not pass list.

Also could be your tab button and the added interference from Line Of Sight. Make sure you have a button that everyone uses to assist your main character and hit this a couple of times before doing anything.