Actual Window | Manager

Now move the mouse to a text field in your browser. Click again. This time, the browser receives the click, moves its own cursor, and starts blinking.

Then came compositing. Now, each window draws to an off-screen buffer—a private canvas. The compositor (often merged with the window manager) then paints all these canvases together, adding shadows, transparency, and animations. actual window manager

This is why "actual window manager" is a slippery phrase. The manager of pixels is the compositor. The actual manager of input is the event router. The actual manager of window state (minimized, maximized, tiled) is a policy engine. Most systems glue these into one process, but they remain conceptually distinct. Part III: A Brief Taxonomy of Actualities If we take "actual" to mean "the software component(s) that physically control window positioning, stacking, and input routing on a modern graphical system," we find not one answer but a family of them. Now move the mouse to a text field in your browser

At this level, there are no windows. There are buffer objects, page flips, and scanout engines. The window manager is a ghost in this machine—a high-level construct that the kernel does not recognize. Then came compositing

Who made that cursor appear? Not the terminal emulator—it has no idea your mouse has entered. The window manager did. It noticed the mouse crossing a boundary, sent a WM_MOUSEENTER event (or the Wayland/X11 equivalent), and the terminal responded by changing its cursor.

We live surrounded by windows. Not the kind that let in light, but the kind that contain spreadsheets, chat threads, and infinite browser tabs. Every day, you drag, resize, minimize, and close these rectangles. You call the software that enables this magic your .