Shows the window and makes it the key window.
This is a convenience method to show the current window and position it in front of all other windows at the same level or lower. If you only want to show the window, change its
hidden property to
Making Windows Key
A Boolean value that indicates whether the window is the key window for the app.
Called automatically to inform the window that it has become the key window.
Called automatically to inform the window that it is no longer the key window.