Add a title and add a subtitle
Edit the subtitle
Edit the color of the subtitle.
By accident, because they are close together, hit the OK button for the subtitle edit instead of the color change.
The menu closes, but at that point DVD styler is hung and I cannot do anything, eventually it crashes or I have to kill it.
When I restart it, I get an error from the OS (Linux) that there is a filesystem error, I may have to reboot the system. I think (not 100% sure) that DVDStyler is unstable at that point and may continue to crash until I reboot.