Broken: 2.80, 2.81...
Short description of error
With region overlap, if a UI element is diabled, clicks are passed through it, which can result in paint strokes.
Exact steps for others to reproduce the error
- Load the default scene and enter Texture Paint mode on the cube.
- Add a paint slot and make a stroke.
- In the UV/Image editor, select the painted image, open the sidebar and switch to Image tab. The UI items should be disabled there now.
- Make sure that sidebar overlaps the image.
- Click on sidebar background.
- Click on any of the disabled items.
In (5), nothing happens. In (6), the click passes through and leaves a paint stroke on the image.