The issue is reproduced when the Theme service of Windows is stopped and classic windows desktop is used

If you dock several tool windows on the same position so that tabs show up and you double click the close button, all remaining docked windows will be made floating.

To reproduce:
- add a dock with ToolWindow and DocumentWindow
- set the following properties:
        ToolWindow1.TabStrip.SizeInfo.SizeMode = Telerik.WinControls.UI.Docking.SplitPanelSizeMode.Absolute
        ToolWindow1.TabStrip.MaximumSize = New Size(94, 400)
        ToolWindow1.TabStrip.SizeInfo.AbsoluteSize = New Size(94, 400)
        ToolWindow1.DefaultFloatingSize = New Size(94, 400)

- Run the app, change the ToolWindow DockState to floating from context menu in the ToolWindow caption
- re-dock the ToolWindow => its sizi is not 94,400 and its SizeMode and AbsoluteSize properties have different values

If you perform the same scenario, but make the ToolWindow floating with drag and drop not with the context menu, everything works fine correctly.

WORKAROUND:
    Private Sub RadDock1_DockStateChanging(sender As Object, e As Telerik.WinControls.UI.Docking.DockStateChangingEventArgs)
        If e.NewWindow Is ToolWindow1 AndAlso e.NewDockState = Telerik.WinControls.UI.Docking.DockState.Docked Then
            e.NewWindow.TabStrip.SizeInfo.SizeMode = Telerik.WinControls.UI.Docking.SplitPanelSizeMode.Absolute
            e.NewWindow.TabStrip.MaximumSize = New Size(94, 400)
            e.NewWindow.TabStrip.SizeInfo.AbsoluteSize = New Size(94, 400)
            e.NewWindow.DefaultFloatingSize = New Size(94, 400)
        End If
    End Sub

The instance of DockWindow is not disposed when the dock's context menu close option "Close", "Close all but this", "Close All" or when the middle mouse button is used for Close operation.

One possible scenario is adding an application menu button like in RadRibbonBar.

Having a 
RadDock control put in a simple RadForm, if in execution time we add a ToolWindow control
 to this RadDock and, in that very moment that the tool window is being painted,
 we alternate between two or more applications using "Alt+Tab" keys repeteadly 
and in a fast way, my application crashes generating an "NullReferenceException". 
The original exception trace is as follows:
 Tipo="NullReferenceException" Mensaje="Referencia a objeto no establecida como instancia de un objeto.
" Source="Telerik.WinControls.RadDock" Trace=" 
en Telerik.WinControls.UI.Docking.RadDockCommandManager.CanProcessMessage(Message msg)

 en Telerik.WinControls.UI.Docking.RadDockCommandManager.Telerik.WinControls.IMessageListener.PreviewMessage(Message& msg)
 
en Telerik.WinControls.RadMessageFilter.NotifyGetMessageEvent(Message& msg)
 en Telerik.WinControls.RadMessageFilter.GetMessageHookProc(Int32 code, IntPtr wParam, IntPtr lParam)
 en System.Windows.Forms.UnsafeNativeMethods.GetMessageW
(MSG& msg, HandleRef hWnd, Int32 uMsgFilterMin, Int32 uMsgFilterMax)
 en System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop
(Int32 dwComponentID, Int32 reason, Int32 pvLoopData)
 en System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
 
en System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
 en System.Windows.Forms.Application.Run(Form mainForm)


The main form inherit from the RadForm.

If we set the AutoHideSize of a ToolWindow to the RadDock size, upon opening the AutoHide window we will notice that there is a gap of about 20px between the edge of RadDock and the AutoHide window.

The text alignment of DocumentTabs does not look good when the tabs are left aligned, the close button is visible and the text is vertically oriented (i.e. it looks horizontal when the tabs are aligned to the left). This would be best addressed if there is mechanism for rotating the Padding value of the Tabs when their alignment is different (left, top, etc.)

I put a tree on toolwindow (the tree Nodes are chekbox)  , when I autohide the toolwindow and show it again the font of tree nodes change and also the nodes which were checked change to uncheck

When you place RadDock with AutoHideAnimation set to None, add several auto-hide windows and you switch between them, you will notice a flickering at the moment of the change.

An editor should appear at where the tabs of RadDock are when the end-user double-clicks the tabs or presses F2. This will allow him to change the text of the tabs.

The ToolTips in RadDock Advanced Layout Designer do not look correctly aligned

Here is a sample application that has the problem. It appears that the issue is easy to reproduce by changing something via the designer in frmMain (like slightly resizing the large close button larger or smaller. Or adding a label or something else in the same DocumentWindow area around the large Close button). 

Here is another issue that might be related with the Designer error I'm pointing out. Using my example Test project, If you add another "Tabbed Document" to the RadDock and then launch the application and go back to the designer and select a tab that is not currently selected in the designer. You will see the errors in the attached screen shots. This causes you to have to close out the designer window and reopen to clear the error.

There should be mechanism for specifying which windows should be saved by the SaveToXml method.

Resolution: 
You need to subscribe to the DockWindowSerializing event to prevent saving of window. Please refer to the following code example: 
void radDock1_DockWindowSerializing(object sender, DockWindowCancelEventArgs e)
{
    if (e.NewWindow.Text == "WindowName")
    {
        e.Cancel = true;
    }
}

In design-time the floating functionality from double click must be disabled.

This is a follow on from the forum entry http://www.telerik.com/community/forums/winforms/dock/toolwindow-theme-error.aspx 

This is not the exact issue I am having but should hopefully lead you in the correct direction. A panels visibility seems to vary depending on where it is.

If you run the program and open a new tool window by clicking the + button you will get a new docked window.
Change this to a tabbed document.
Then add another window and set it to be docked.
Then add another window and also set it to be docked. Then set it to autohide.

You will see on the tabbed document and the docked unautohide window that there are 2 lines of text. If you now let the auto toolwindow open you will see that there are now three lines of text in this window. The docked autohide is letting the text shine through but only when it is in this state.

To reproduce:
- create a VB project
- open the advanced layout designer and add few windows in it
- save it and the windows will not show on the form

using the RadDock component in a product that must support multiple montors.  I see some mention of this in the support forums, but I would like to confirm with you that RadDock does support docking on multiple monitors with dragging of panes/panels between monitors and full serialization of the layout on multiple displays. Add support to move and maximize DocumentWindow and ToolWindow in multimonitor system.

Xml serialization not work in scenarios with inherited ToolWindow