NP. Thanks for making the thing
Actually, though, this happens pretty frequently for me.
Specifically - I dock the window on the left. I'll mouse over to the window to pop the larger version, click on a target and then start mousing up to the arrow to track. If I hover too long over one of the other names, it will highlite that mob instead. To get around this I've taken to clicking the mob I want, mousing to the right, off the window until the font size drops again and then carefully moving my mouse up and over so as to get my cursor right over the arrow icon before the size pops again.