1235a914cd
Joining and Docking tag the source and target areas for redrawing. But there are times when areas are split and recombined as part of the processes. In some cases areas that are not either source or target must also be tagged for redraw. Especially for Outliner and 3DView as they try to avoid full redraws with RGN_DRAW_NO_REBUILD, but needed here. Pull Request: https://projects.blender.org/blender/blender/pulls/130801