I played around a bit to figure this out, but there a a couple of settings that won't save, even if I save current settings as default. I clean-installed FPSE, then changed the video mode to High Definition OpenGL. I quit the program and opened it again, then set a few video settings, including Forc...

Seems the option does not work with OpenGL ES 2.0 Blitting enabled. If you go back to old software rendering, it works.

Seems the special screen size options are not working. Both the setting to set the screen size and the option to turn the mode on do not say enabled after leaving the screen they are set on.