Edit per pixel frames vs Edit UIS1/2 frames?
In short: what is the difference between 'Edit per pixel frames' and 'Edit UIS1/2 frames'?
When you start a new skin, (SKS 11), and you go to 'Edit TitleBars and WindowFrames',
then there are two options to define the frame, 'Edit per pixel frames' and 'Edit UIS1/2 frames'.
Both of them use (different) images to define a frame.
I find this confusing because obviously,
the skin can only use one frame, so why are there then two definitions ?
