true if the floating window is valid (whether it contains a LayoutAnchorablePaneGroup root panel); false otherwise.
Remarks
ets whether the floating window is valid (whether RootPanel is null) rue if the floating window is valid (whether it contains a LayoutAnchorablePaneGroup root panel); false otherwise
Requirements
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