more details about this behavior.
it looks like it's dependent on the AI being over the item. i am unable to replicate nofish's behavior
i'm in win10x64, nofish, what about you?
if no item exists under the AI, it's possible to right click multiple selected AI
if an item DOES exist under the AI, it's impossible to do this, regardless of how carefully you don't move the mouse. i'm over here confirming that the mouse doesn't move at all while right clicking, and i still lose selection
note in the below gif how the only way to keep multiple AI selected while right clicking is by clicking the itemless area.