Plugin Toolbars not docking in areas other than upper area

There is a Qt bug with docking toolbars. It has to do with a Win system setting for “show window contents while dragging” (or similar.) I think if your system is set to only show the window outline, then it is difficult to impossible to drag & dock toolbars.

See this post with screen snip by @dezmo


Also, same thread, Paul suggests that it is important where you grab the toolbar with the mouse: