Made in GIMP, which was a challenge this time. I was happy to get a stable version running on my new MacPro, but handling kind of changed it seems. I was constantly struggling with brush settings (seemingly) randomly resetting or changing, or dialogues getting locked, so I had to reopen the program to fix it again and again. I still have no clue why the locking happens, but the resetting brushes are obviously a "feature". Turns out GIMP saves tool settings per "type" of pointer you use, so one for the mouse, one for the pen away from the tablet, and one for the pen close to the tablet. So as soon as you move the mouse, it switches back to the "mouse pointer tool settings".
It's probably the most annoying "feature" I ever came across, and I do hope I find a way to deactivate this.