Windows 7 64bits
It's broken since I remember, only that I ignored the problem.
Short description of error
When you uses multiple windows in same blender instance and a wacom tablet blender lost the pressure or "focus" of the wacom and only go back when you click in the secondary window. And sometimes blender don't paint the grease pencils
The bug affect to painting modes, sculpt, and grease pencil drawing. The problem, that I was ignored because click in the secondary window to obtain presure is not a big problem. But now I have see that also you can have problems with grease pencil, creating "invisible" strokes that don't work with bsurfaces. Blocking the workflow until you "imagine" the problem or close and open blender other time.
Exact steps for others to reproduce the error
- Open Blender and create a secondary window with 3D view (in my test work with other panels themes)
- Click in the secondary window
- Open other program, browser for example (chrome)
- hide the secondary window
- focus in chrome
- focus in primary 3D view
- Try to paint
-In my test it works with windows in different or same monitor, I don't know if it affects to the problem.
-Some times it doesn't work and you must try so iterations of Blender -> Chrome ->Blender -> hide secondary. But I obtain it making few iterations, in less that one minute