Visibility and IsEnabled on ToolWindow do not work

I would like to be able to hide or show the window based on a specific UI Behaviour.

Visibility="Hidden" and IsEnabled="False" do not seem to work on a ToolWindow. Is this a Bug?

For Example:
<controls:FwDockSite x:Name="CentreWorkspaceRegionPanel" Grid.Row="0" Background="Transparent">
<docking:Workspace>
<docking:TabbedMdiHost>
</docking:TabbedMdiHost>
</docking:Workspace>
<docking:DockSite.AutoHideRightContainers>
<docking:ToolWindowContainer x:Name="RightWorkspaceRegionPanel">
<controls:FwSearchWindow Visibility="Hidden" IsEnabled="False" Title="Test" CanAttach="False" CanAutoHide="True" CanBecomeDocument="False" CanClose="False" CanDockBottom="False" CanDockLeft="False" CanDockRight="True" CanDockTop="False" CanDrag="False" CanRaft="False" HasTitleBar="True">

</controls:FwSearchWindow>
</docking:ToolWindowContainer>
</docking:DockSite.AutoHideRightContainers>

</controls:FwDockSite>