Thomas said:
No, it is a feature of the window manager, in 32+ bit Windows that is
explorer.exe by default. Only Windows tries and inevitably fails to
unite both in one big working piece of software.
No, it is not a feature of the window manager. It is a feature of the
gdi32.dll component responsible for drawing the non-client area of windows.
I would say that gdi32.dll *is* part of the OS.
The actual handling of, say, a mouse click on the X is also handled by
gdi32.dll as part of the default handling for windows messages.
gdi32.dll has nothing at all to do with explorer.exe, other than the fact
that explorer.exe, being simply an application, uses gdi32.dll to handle
its non-client area and other windows related functions.
Also, explorer.exe has nothing to do at all with window management. It is
merely a program responsible for displaying the contents of folders,
allowing the user to manipulate said contents, and allowing the user to
launch applications. You can even shut down explorer.exe (with task
manager) and the desktop and all "windows management" functions will
continue to operate normally.