give visual feedback when DnD'ing window buttons

Submitted by Liv

Assigned to Nick Schermer

Link to original bug (#11532)

Description

From memory, in 4.8 it was possible to DnD window buttons and there was a visual indicator showing the user the place were the Dragged-and-dropped button would end up. In 4.10 DnD was initially dropped, then re-introduced. But the visual indicator got lost along the way.

A DnD visual indication would be useful for those who use None, allow Drag-and-Drop sorting order for the window buttons. The indicator could be not unlike what happens when you right-click on panel item > Move and then hover the mouse over other panel items...

Version: Unspecified