Deskbar (BeOS)
BeOS's combined launcher, window list and status tray, tucked into a small panel in the top-right corner of the screen.
Where Windows 95 stretched a taskbar across the entire bottom edge, BeOS made do with a corner. At the top sat the Be menu with the applications; below it a list of running programs, each of which expanded into its windows; and at the bottom a clock and a tray of small status icons. Those icons were replicants, the BeOS mechanism for letting one program embed a live piece of itself inside another. Deskbar could be dragged to other edges and laid out horizontally, but most people left it where it was.
Deskbar and Tracker together were the entire desktop. Both were released as open source in 2001 as Be Inc. went under, and Haiku's Deskbar is the same program in a direct line of descent.