Returns or sets a boolean value that determines whether or not Select dropdown controls will be automatically hidden when submenus are being displayed.
When this property is set to true, all select controls in the page document are hidden until the popup menus are dismissed.
This functionality is necessary due to the problematic way that Internet Explorer implements the Select DropDown control. Netscape 6+ handles this situation properly and the hiding of dropdowns is not necessary.
Target Platforms: Windows 10, Windows 8.1, Windows 8, 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