Very interesting, I use a MBP Retina for development and have 2 screens however when at home my two screens are just 1920x1200's. I'll have to open up my retina screen and see if i can reproduce this.
Thanks for reporting this.
I'm hoping its something that is fixed in JRE8 since that looks more like a core java issue. We will be releasing a new Minion soon(tm) that upgrades it from JRE7 to 8. So far many small edge case bugs have been ironed out because of this and I've seen some nice performance boosts too.
Also on OSX if you always use the X on the upper right corner to close Minion it will close just fine. There is an issue with the hooks it uses when closing Minion using an apple method (Command-Q, right click Quit, etc). We are working on this too.