An application sends a CB_SETEXTENDEDUI message to select either the default user interface or the extended user interface for a combo box that has the CBS_DROPDOWN or CBS_DROPDOWNLIST style.
CB_SETEXTENDEDUI
wParam = (WPARAM) (BOOL) fExtended; // extended user interface flag
lParam = 0; // not used; must be zero
Parameters
fExtended
Value of wParam. Specifies whether the combo box uses the extended user interface or the default user interface. A value of TRUE selects the extended user interface; a value of FALSE selects the standard user interface.
Return Values
If the operation succeeds, the return value is CB_OKAY. If an error occurs, it is CB_ERR.
Remarks
By default, the F4 key opens or closes the list and the DOWN ARROW changes the current selection. In the extended user interface, the F4 key is disabled and the DOWN ARROW key opens the drop-down list.
See Also