[pseudalopex]

Haiku has stackable tabs instead of title bars.[1] KDE used to let you group windows as tabs.[2] Microsoft experimented with it.[3]

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

[2] https://superuser.com/questions/848840/triggering-kdes-attac...

[3] https://www.zdnet.com/article/windows-10s-sets-feature-is-go...