A set of replacement system window controls is provided that are instantiated as the result of the receipt of create control messages into the system message queue, instead of the built-in system window controls. The replacement window controls result in replacement control instances being created with modified properties based on user preferences. The replacement system window control instances may also include an overlay function. In response to a set focus message, a replacement control instance may create an overlay control that is displayed over the replacement control. The overlay control itself can have modified properties and may be enlarged or relocated. When the overlay control receives a release focus message, the overlay control passes its state back to the replacement control and is destroyed.