Auto-hide menus and viewports like windows taskbar

(pics at bottom)

Same kind of behaviour as windows task bar. You can hide the taskbar and have it come up when you place your mouse near the bottom (or any edge) of the screen (I call it auto-hide). In blender this allows you to leave the n and t menus on all the time for example and they only show up when you move your mouse there. The menus when auto-hidden won't disappear completely when hidden but leave visible may 15 pixels wide/tall to visually indicate they are hidden. I think having it user option to choose whether to hide them completely (like windows taskbar) or just partially is also a good idea.

I'd like to have this toggleable from the ui as a button. Now there are the [+] icon buttons there for n and t menus. I'd add a second button there (in the image sample I have it as blue [+] icon) which would turn on the behaviour in this suggestion for that toolbar. Having it configurable for each toolbar in the viewports is a huge plus as some people may want to auto-hide more than others. Some may want to hide even the top bar while I think most would just hide the n and t menus.

But I'd also want to add this feature for viewports. Imagine if you could make the timeline auto-hide? Or even the whole right side menu? I think this can be really powerful. You can for example set up two workspaces that "switch" when you move your mouse to top or bottom of the screen so you can switch between modelling and uv editing workspaces really really fast by simply moving your mouse over the autohidden viewport edge. This is much faster and less wrist hurting than trying to grab the really narrow viewport edges for example.

I'd not hide this functionality behind keyboard shortcut as that makes it almost impossible to discover. But the icon placement on some places could be problematic as you never want a situation where this new icon is on top of a button you need for example. I'd also have this option available from the right click menu when you click on viewport edge to split/join.

The problem with auto-hide is that how to make this behave when you have set multiple objects to auto-hide next to each other. For example if you hide the whole right side menu and the n menu. Technically you could hide so many viewports that when you mouse hover over the unhidden menus don't even fit on screen. This is a rare problem but I have couple of suggestion how to fix it. You can either prevent it by setting a maximum (max of autohidden menus next to each other, max width/height) or just alow it and have a scroll bar so the user can pan all the menus while holding the mmb for example.

Another issue is when the auto-hidden menu is wider than the space it has when it needs to popup. Do you scale the whole view to give it enough space or do you just move the viewport edges momentarily to give it the space? I'd go for the latter.

There is also the question of how much does the viewport auto-hide. Is 15 pixels too little or too much. Do these aujtohidden menus need to stand out visually in some way to indicate they are auto-hidden and not just dragged narrow?

Two sample image showing the feature in use. In the first image the timeline and the n menu are autohidden:

In the second one whole bottom workspace (uv and shader viewports) and the right side menu are autohidden and I added a blue highlight to the hidden menus.

Third one is another trick you can do with this (timeline autohidden in the middle of the screen)