This happens when the resizer is moved to max right (for example) and then the orientation is changed. 

1. Create a raddocking control inside of a radwindow.
2. Add a few docks.
3. Drag a dock and drop it in a floating position.
4. Drag another dock.
5. As you drag the 2nd dock the first one disappears. It's somehow falling behind the raddocking control.

When using the UnpinAllPanes/PinAllPanes methods of a RadPaneGroup inside the Pin/Unpin events only the clicked RadPane is pinned/unpinned. If a Dispatcher is added all the RadPane instances are pinned/unpinned but after multiple pins/unpins sometimes the unpinned RadPane Headers become selected and the AutoHideArea is not longer expanded.

I would like OverflowMode to work for all RadPaneGroup in xaml/codebehind and this be persisted through SaveLayout/LoadLayout.

For example:

<telerik:RadDocking.DocumentHost>
    <telerik:RadSplitContainer x:Name="MainContainer"
                                           Orientation="Vertical">
					<telerik:RadPaneGroup ScrollMode="Item"
                                          x:Name="GroupMainTop"
                                          OverflowMode="Scroll"
                                          ScrollViewer.HorizontalScrollBarVisibility="Auto"
                                          cal:RegionManager.RegionName="RegionMainTop"
                                          telerik:ProportionalStackPanel.RelativeSize="150, 400" />

Works, but when I do:

        private void LoadLayoutInternal(XElement xml)
        {
            using (MemoryStream stream = new MemoryStream())
            {
                xml.Save(stream);
                stream.Seek(0, SeekOrigin.Begin);
                this.Docking.LoadLayout(stream);
            }
            Dispatcher.BeginInvoke(() => FixDockProperties());
        }

The RadPaneGroup no longer has OverFlowMode Scroll

When I try to fix this in code behind, this has no effect:

        private void FixDockProperties()
        {
            // Fix diverse properties die door laden van de layout verloren zijn gegaan.
            // Dat lijkt niet te werken, ik heb Telerik gevraagd waarom dat is:
            // http://www.telerik.com/forums/overflowmode=-scroll-disappears-when-i-save-load-layout#mwEJP5eh8EG4TbNqfnd00g
            GroupMainTop.OverflowMode = Telerik.Windows.Controls.TabControl.TabOverflowMode.Scroll;
            GroupMainTop.SetValue(ScrollViewer.HorizontalScrollBarVisibilityProperty, ScrollBarVisibility.Auto);
            GroupMainTop.ScrollMode = TabControlScrollMode.Item;

When the IsHidden property of Pane is set to true at startup the Pane is shown and immediately hidden.

Message: "Value does not fall within the expected range."StackTrace = "at MS.Internal.XcpImports.CheckHResult(UInt32 hr)   at MS.Internal.XcpImports.SetValue(IManagedPeerBase obj, DependencyProperty property, Boolean b)   at System.Windows.DependencyObject.SetValue(DependencyProperty property, Boolean b)   at System.Windows.Controls.Primitives.Popup.set_IsOpen(Boolean value)   at Telerik.Windows.Controls.InternalWindow.MultiplePopupWindowHost.PopupHostManager.ClosePopup()   at Telerik.Windows.Controls.InternalWindow.MultiplePopupWindowHost.Close()   at Telerik.Windows.Controls.WindowBase.CloseWithoutEventsAndAnimations()   at Telerik.Windows.Controls.Docking.ToolWindow.Hide()   at Telerik.Windows.Controls.RadDocking.<OnUnloaded>b__26()"

The issue is present in some of the themes.