[power-pro] bug in bar popup code

[das_e_i]

Hello,

I just noticed a small bug in the "popup at screen edge" function. 
When "Bar Size from sum of all buttons" is checked, you can't move 
the mouse parallel along the edge to the area where the bar is 
located, but you have to move the cursor from the center of the 
screen to the edge. So that code should also contain a check for this 
condition I think.