It would be nice if one could hide/show the tool bars (left and top) and also the menu bar, for example by hitting "TAB". It is so easy to use the application with just keystrokes, and this would make for a "cleaner" appearance, for example when used while teaching. "TAB" also seems sensible given that other applications (e.g. gimp, darktable) use this key for the same purpose.

I guess this could be implemented with a simple call to show() and hide() of the menubar and toolbar widgets.