This simplifies the feedback shown while using the "Interactive Editor
Docking" experimental feature. It removes the "X" icon shown on areas
that are removed. It does not show an icon for the areas that are left
over and altered. It only shows an icon for the active target area, and
does so without the outline of the icon. The result is a calmer
experience and it is easier to see exactly where the area is going.
Pull Request: https://projects.blender.org/blender/blender/pulls/126304
8f996f1786