Setting the size of a docked toolwindow?

I create a new tab, to a raddock, but when I try and switch back to another tab, I get

System.NullReferenceException: Object reference not set to an instance of an object.
   at Telerik.WinControls.UI.Docking.DockTabStrip.ProcessFocusRequested(RadElement element)

How do i fix this?

Thanks.

I have a document container with 3 tabs on it as the attached snap show.  Each of them works fine right now, and I can switch between them.

I needed to add another one. From the radDock tab I clicked and did, "Add Tabbed Document". This works fine.

Whens I run the code though, when I try and click on the other tabs it crashes, and the I get the above stack trace.

Hi dear admin !

Can i fix radDock toolwindow size ?

I want  restrict toolwindow minimum or maximum size on runtime by user.

Hello Gh Reza,

Thank you for writing.

In order to restrict the size of a toolwindow, you can use the MinimumSize and MaximumSize properties. Here is an example that demonstrates how you can fix the tool windows height:

 public RadForm1()
        {
            InitializeComponent();

            ToolWindow window1 = new ToolWindow();
            ToolWindow window2 = new ToolWindow();
            ToolWindow window3 = new ToolWindow();

            this.radDock1.DockWindow(window1, DockPosition.Top);
            this.radDock1.DockWindow(window2, DockPosition.Top);
            this.radDock1.DockWindow(window3, DockPosition.Top);

            window1.TabStrip.SizeInfo.MinimumSize = new System.Drawing.Size(0, 100);
            window2.TabStrip.SizeInfo.MinimumSize = new System.Drawing.Size(0, 100);
            window3.TabStrip.SizeInfo.MinimumSize = new System.Drawing.Size(0, 100);


            window1.TabStrip.SizeInfo.MaximumSize = new System.Drawing.Size(0, 300);
            window2.TabStrip.SizeInfo.MaximumSize = new System.Drawing.Size(0, 300);
            window3.TabStrip.SizeInfo.MaximumSize = new System.Drawing.Size(0, 300);
        }

Additional information about RadDoc is available in the following help article: https://docs.telerik.com/devtools/winforms/controls/dock/object-model/example-building-an-advanced-layout-at-runtime

I hope this helps. Should you have other questions do not hesitate to ask.

Regards,
Nadya
Progress Telerik