cannot copy files between Explorer tabs by hovering over other target tab

Sorry I think the mailer must have been a little unclear.

If whilst dragging you drag over a groupy tab, pause for say half a second, it should change to that tab allowing you to them drop the files in the explorer window (or other app).  You cannot drop directly on the tab (it wouldn't know which part of the window you wanted to drag it to)

Alright, that makes sense; first hover over the target tab to activate it, then move down and drop the file into the *folder window* of* the target tab (not try to drop onto the tab itself). TNX for super-fast clarification!