Left click boxes opening

I'm being trying to figure out some funny mouse happenings to see what program might be causing the problem.
Sometimes when I attempt to select several words in a sentence the high lite stops during the drag operation and thhe edit box appears. I might try this several times before it finally works correctly. Other times the edit box appears when I select a Bookmark in FireFox. I just now hit Enter and the FF file menu box appeared.
What could be causing this? Is it something that I checked by mistake?

Check to see if you have Sticky Keys turned on. Sometimes if your ALT key is down, you may be actually doing other commands.

Sticky keys are not on. i'm beginning to suspect the new wireless mouse I installed.

That's possible. If you still have the old mouse (or another mouse of any kind for that matter) swap it back out and see what happens.