changing setting so active window changes without clicking

[jdl22]

I'm quite sure this has been posted before, but a search came up empty.

I want to change the settings so that the window that is active will change if I drag my mouse over another window. For example, suppose I'm playing two tables, A and B. I click fold on table A then drag my mouse over table B. Table B now becomes active so that I can fold my aces preflop with one click instead of the two or three it normally takes.

How is this done? I have tweakUI but I couldn't find this there.