Haiku retained all of this and bring something new like combining various windows into single tabbed one - not sure if any other system has such feature. Or... toolbar in file manager - which is something I really missed back then in BeOS.
Back then BeOS was much more stable and faster than my daily Win98SE, even working in that image file on FAT32 partition.
Kinda makes you wonder, how things would go if Apple would pick BeOS as their OS instead of Jobs' NeXT. Would it still looks same or it would go thru all stages we've seen - with glass, transparency and then flatness and darkpatterns producing minimalism.