A modal Popup will not close when the user clicks away from its Content.
The default value is false, which will create a Popup that closes when the user clicks elsewhere than on the Content.
Target Platforms: Windows 11, Windows 10, 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