This is very stupid question maybe, but I couldn't find out the solution.
When I want to select several objects in one mouse move I just selecting them using the selection tool (pressing, moving from one corner to another and releasing). If I want to add another several objects to selection, I just use Shift button.
But the question is: how to remove several objects from selection in one mouse move?
In Illustrator I use Shift button again, but it doesn't work for Flash.