: Because there was no central "compositor" to manage these layers, the dwm.exe process simply was not part of the operating system. What is DWM.exe?

Introduced in 2006 with Windows Vista, dwm.exe changed how Windows handles graphics by becoming a . Instead of drawing directly to the screen, every program writes its window to a private buffer in memory. The DWM then "composites" all these private buffers into one final image for your monitor.

: Each application was responsible for drawing its own interface directly to the main screen buffer.

In , Microsoft used a "stacking" window manager. In this older architecture: