Drag n Drop not opening anything

Hi,
Grag n dropping PNG files over the interface (whichever part) won't open files, even though the icon when hovering suggest it will.
Nothing is logged in the Displayable debug info (CTRL+D)

Reproduce the problem by dragging PNG files over different parts of the interface and check the Displayable debug info with Ctrl+D. Trace the drag-and-drop entry point and determine why no file-opening action or debug output occurs; done means PNG drops open successfully and the behavior is visible in the debug information.

Written by the indexing model from the issue text.