I really wish GIMP had View -> Show -> None/All
that Photoshop has in addition to having View -> Show/Hide Selection
and Show/Hide Guides
that already exist individually.
My work (cleaning comic book drawings) often involves “pixel-staring”… When I want to check if my stroke looks natural, I need to deselect the pen tool and hide the active path, switch away from the tools because they cover the work.
When I’m in this situation I wish I could just take a quick peek of how the image actually looks like, just by pressing a button toggle (keyboard shortcut).
This is also requested in StackExchange thread that I read first: GIMP: Toggle show/hide all non print extras - Graphic Design Stack Exchange