If the list portion is already visible, the DropDown method does nothing and returns true.
When the DropDown method is called, the BeforeDropDown event is fired. If the event is canceled, the list portion is not displayed, and the AfterDropDown event is not fired. In that case, the DropDown method will return false.
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Server 2012, Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2