=== What is the enhancement in mind? How should it look and feel? ===

In addition to all of the other "hide when..." settings, I would love to have certain bars hidden unless I hold down a non-modifier key, such as <`> (tilde).  It would basically function like mouseover autohide, except it would show bars when a button is held.

=== Please provide any additional information below. ===

As I am getting more comfortable with my keybinds, I find that I don't need to see my buttons as much.  However, as an altaholic, I often need a quick reminder, and often in combat.  I would like to be able to bind any key other than just ctrl, alt, or shift, to control visibility.  For example the tilde key, F12 or whatever.  It is important that the key used to momentarily show the bars only modifies visibility and does not modify the keybinds.

Since I want a set of keybinds to work whether the bars are displayed or not, using a modifier (ctrl/alt/shift) to control visibility is problematic.  For example, let's I have a bar for Q,E,R,T,Y,U and Frostbolt is bound to E.  Normally, the bar is hidden but works just fine.  I could set the visibility to show only when I hold down alt, but then it isn't a reminder that my Frostbolt is bound to E anymore... it'll show aE as the keybind.  Not such a huge deal if you ignore the a, but for users like me that use modifiers extensively, it limits the number of binds, it takes mental energy that should be spent on combat, and it gets more complex when you have to remember that ascE it really just scE.

You might suggest just using the mouseover autohide, but a big reason I want this feature is to free up the space for other UI elements.  My normally-hidden bars would be places in a location that would interfere with mouse movement and such.  The constant flickering of action bars would be very distracting.  I also want to immediately but momentarily see all of my bars, not one at a time.

I see there are other requests for a slash command, and that would work for folks that only want to toggle visibility to manage their buttons then hide them again.  I could possibly just create a macro and bind it to the key of my choice.  It just doesn't seem as clean.