Get window handle of last activated window

Question

I am developing an application that sits in the system tray and can perform actions on the active window. But when the icon in the system tray is clicked, GetForegroundWindow() returns the taskbar. I need to get the window that was active before the taskbar was.

I've tried enumerating the desktop window with EnumWindows and GetWindow, but this is often turning up desktop gadgets and other top items that where not active last. Is it even possible, or the information completely lost when the window is deactivated?

Answer 1

I think the only way to get that info is by installing a system wide hook (SetWindowsHookEx) on WH_CALLWNDPROC and capturing all WM_ACTIVATEAPP. This will even enable you to track the full history of which window was active when.