I have seen the occasional reports of problems selecting text with the mouse with VA installed, but so far I have been unable to reproduce this problem in any recent version of VA.
You should not have had this problem, VA should work fine after installing it. I am glad the problem has gone away. Hopefully you will not see it again, but if you do please tell us, and we will try to find out what is going wrong.
Had it myself recently under 1639, but seriously i feel its not VAX related at all. It seems to be related to VS itself. Its not the first time I had it and seems to happen when other addins like source control are involved that open up dialogs in the background and modify current windows editability. Sometimes it goes away by closing the source code window, sometimes you have to restart the ide.