WeifenLuo DockPanelSuite opening a new Document fails with Object reference not set to an instance of an object

Question

A very frustrating error is being thrown in the below code:

try
            {
                FrmRestrictedWebBrowser frmRWB2 = new FrmRestrictedWebBrowser();
                    frmRWB2.Show(dockPanel, DockState.Document);
                frmRWB2.ShowSrcUrl(eur.LinkUrl);

            }
            catch (Exception ex)
            {
                string err = ex.Message;
                throw;
            }

The Error: Stack trace

at WeifenLuo.WinFormsUI.Docking.DockPanel.FocusManagerImpl.SuspendFocusTracking() at WeifenLuo.WinFormsUI.Docking.DockPanel.SuspendLayout(Boolean allWindows) at WeifenLuo.WinFormsUI.Docking.DockContentHandler.Show(DockPanel dockPanel, DockState dockState) at WeifenLuo.WinFormsUI.Docking.DockContent.Show(DockPanel dockPanel, DockState dockState) at Imogen.frmMain.ProcessUnReported(EUReported eur) in C:\Users\Dave\Documents\Visual Studio 2015\Projects\Imogen\Imogen\frmMain.cs:line 244

Error Message:

Object reference not set to an instance of an object.

As you can see all I am doing is creating a new form and trying to show it. Everything says that it is working until the .Show(dockPanel, DockState.Document) The Form and the dockPanel exist and have handles so I don't know what is going on.

Any ideas?