Normally windows hide all windows on all monitors when WIN+D is pressed. This tray application instead hides only windows on the monitor with either

• the active focused window,
• or the monitor where the mouse is (if started with --mouse command line option)

Specifically, it uses a low-level keyboard hook to capture the keypress and prevent the default behavior of WIN+D. When the keypress is triggered it enumerates all windows and filters away those that are special, hidden, or not on the monitor with the currently focused window. To terminate the application it also adds a tray icon that can be right-clicked and to exit the program.

Unlike the default windows implementation which unhides the same windows just hidden on re-press if no changes has been made to any of the windows since the initial press, this does not unhide windows.