[lloeki]

> I love the idea of all application windows being able to be moved into tab groups. Are there window managers that do similar things?

Haiku Stack&Tile!

https://www.haiku-os.org/docs/userguide/en/gui.html#stack-ti...

A long time ago I implemented something like it (the stack part, not the tile part) in Awesome/Lua, so that floating windows could be tabbed together. Code is lost though. It was a bit too buggy anyway, pushing Awesome to its limits.

[sprash]

Pekwm[1] does this and is still actively developed. One of my favorite floating WMs.

1.:https://github.com/pekwm/pekwm

[rollcat]

I think one of the old X11 window managers could mimic that behavior as well, when using the BeOS skin... It might've been KWin around KDE3 series, but my memory might be failing me.