CNTRL Structure Describing a Button Control

dwType: Property that is used to perform an action. This value MUST be the PidTagAddressBookManageDistributionList property, as specified in [MS-OXOABK] section If this value is anything else, it MUST be ignored.

ulSize: MUST be 0x00000000 and MUST be ignored.

ulString: String that contains the label text of the button control. The string MUST NOT be greater than 128 bytes in length, including the NULL-terminating character.