In addition to the button (and hotkey) access to displaying a folder tree in each panel (my request here), it would be great if the folder trees could show/hide themselves automatically in response to mouse movements.
I conceive of a narrow vertical stripe adjacent to a file panel boundary that is active to "unhide" the file system tree panel (plus the favorites tree(s)... see my previous request here) when the mouse pointer lies over it for a short time.
NetCaptor, Maxthon, Opera, Corel PaintShopPro and many other softwares implement a similar behavior.
Perhaps the mouse-active region could display tabs allowing us to choose to "unhide" either the system folder tree or a specific favorites group. This design is also implemented in several of the above software examples.
Naturally, such a panel would require a "pushpin" toggle control to prevent it from hiding after a selection had been made, should the user require it.
REQST: Dual folder trees No. 2: mouse-over hide/show
REQST: Dual folder trees No. 2: mouse-over hide/show
Mouse-centric, Registered