OT fixes up selection even in textareas that aren't focused

[ianb]

This site can demostrate the problem.

If I am editing field 1, and another person is editing field 2, when they make a change the algorithm will set/fix-up my selection in field 2, which also focuses field 2. This, as you might imagine, causes craziness.

/cc @cscott

[cscott]

Oh, interesting!