The CreateHandle method calls CreateWnd to handle the particulars of creating the combo box window. TCustomCombo overrides the inherited method to ensure that the newly-created window and the TCustomCombo properties correctly reflect each other. 

The Windows control for the combo box can be temporarily destroyed and recreated in order to set properties that require changing the window creation parameters. Thus, CreateWnd may be called more than once during the lifetime of the TCustomCombo instance. 

CreateHandle