rudle
commented
9 years ago huh, that's a weird bug! I don't think it's specific to maximum-awesome though. I was able to reproduce the error with a minimal .vimrc just: set mouse=a.
If you're so inclined, you might submit a bug upstream to https://code.google.com/p/vim/
When highlighting over the third vertical window pane (far right) the left most pane is the one highlighted.
Currently only the two left windows can be selected or scrolled: