Call SendCancelMode to cancel the modal state of the control. Various controls implemented in the VCL support a model state where the user must respond to the control before interacting with any other object on the form. An example is the dropped-down state of a combo box when the drop-down list is showing. For these controls, specific user actions send a Windows message to the control to end the model state, such as a mouse click that closes up the dropped-down list. 

SendCancelMode allows an application to end the modal state of the control in the absence of a user action, or when implementing a new user interface response. 

Perform 

DroppedDown