> Technically, a window manager can do all that, including the hierarchy. I could envision a WM that allows you to group windows together into tabs or sub-windo

> Technically, a window manager can do all that, including the hierarchy. I could envision a WM that allows you to group windows together into tabs or sub-windows. I think Microsoft did something like that with tabs, but I don't know how popular it was/is. Haiku definitely does this (and apparently even the original BeOS did), although for all that the window headers even look like tabs I never stumbled upon it until I saw it mentioned in the manual[1]. I also don’t think it does anything special when the windows in such a group spawn new ones, which would probably be half the joy in such a tiling-like interface (probably because its WM doesn’t really have a notion of a window spawning another one, so if the same application has two of its windows in different such groups and then creates a third one, the WM can’t really tell where the third one should go). Crackpot idea: go all the way to tree-style tabs[2] and move history into the window manager, too. With enough (probably too much) imagination you could even see how Miller columns[3] would emerge. [1] https://www.haiku-os.org/docs/userguide/en/gui.html#stack-tile https://www.haiku-os.org/docs/userguide/en/gui.html#stack-ti... [2] https://github.com/piroor/treestyletab https://github.com/piroor/treestyletab [3] https://en.m.wikipedia.org/wiki/Miller_columns https://en.m.wikipedia.org/wiki/Miller_columns