This is a strange one, and you have to something very specific to make it happen - might not even be your fault, maybe it's Apples bug. In version 3.5, I can make Lux unresponsive by doing the following:
Run Lux
Click the color well fora player color
When the color window pops up, choose the sliders option
Choose the grayscale slider option
Choose any shade of gray
Close the color window
The program is now jammed. You can't quit, you can't start a game. Well actually, you can quit, but only from the dock. It's like the event loop for Lux is not happening.
EDIT: Just remembered - you can get Lux out of stuckness by clicking well the color and choosing something else (not from the grayscale slider).
Freezing Lux with the grayscale slider.
Indeed this is a wacky bug. Thanks for the concrete steps to reproduce it. Turns out that at one point I would extract the red/green/blue components of the color without first making sure it was in the RGB color space. So if a non RGB color (i.e. a grayscale color) was used it would activate this bug.
It has been fixed in the codebase for the next release.
It has been fixed in the codebase for the next release.