In rare scenarios, you might need to detect unexpected input. For example, consider the following scenarios.
During a mouse operation, the user opens the Start menu by pressing the Windows key or CTRL+ESC.
During a mouse operation, the user switches to another program by pressing ALT+TAB.
During a mouse operation, another program displays a window or a message box that takes focus away from the current application.
Mouse operations can include clicking and holding the mouse on a form or a control, or performing a mouse drag operation. If you have to detect when a form or a control loses mouse capture for these and related unexpected scenarios, you can use the Control.MouseCaptureChanged event.