Swap between visible and hidden items

[macaelero]

Just like bartender does. When you have a lot of icons (istat menus, sync tools, tg pro...) is quite useful to swap between the current visible items and the hidden ones. It should be a nice addition, since I prefer this feature instead a second floating bar. BTW, nice app, congrats!

[jordanbaird]

Thanks! We already have #240 to track this, btw.