NullReferenceException when changing to split type 'None'

Hey,

I get the following exception after changing the split type to NONE:

System.NullReferenceException was unhandled by user code
Message="Object reference not set to an instance of an object."
Source="ActiproSoftware.SyntaxEditor.Net20"
StackTrace:
at ActiproSoftware.SyntaxEditor.EditorView.a(Token A_0, Boolean A_1, MouseEventArgs A_2)
at ActiproSoftware.SyntaxEditor.EditorView.OnMouseLeave(MouseEventArgs e)
at ActiproSoftware.WinUICore.UIElement.ActiproSoftware.WinUICore.IInputElement.RaiseMouseLeaveEvent(MouseEventArgs e)
at ActiproSoftware.WinUICore.UIControl.a(IUIElement A_0, MouseEventArgs A_1)
at ActiproSoftware.WinUICore.UIControl.OnMouseLeave(EventArgs e)
at ActiproSoftware.SyntaxEditor.SyntaxEditor.OnMouseLeave(EventArgs e)
at System.Windows.Forms.Control.WmDestroy(Message& m)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
at ActiproSoftware.SyntaxEditor.SyntaxEditor.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
at System.Windows.Forms.UnsafeNativeMethods.IntDestroyWindow(HandleRef hWnd)
at System.Windows.Forms.UnsafeNativeMethods.DestroyWindow(HandleRef hWnd)
at System.Windows.Forms.NativeWindow.DestroyHandle()
at System.Windows.Forms.Control.DestroyHandle()
at System.Windows.Forms.Control.Dispose(Boolean disposing)
at System.Windows.Forms.Form.Dispose(Boolean disposing)
at Watchfire.AppScan.Gui.MainFormUserControls.Form1.Dispose(Boolean disposing) in C:\AppScanReports\SyntaxEditor\SyntaxEditorTest\SyntaxEditorTest\Form1.Designer.cs:line 20
at System.ComponentModel.Component.Dispose()
at System.Windows.Forms.ApplicationContext.Dispose(Boolean disposing)
at System.Windows.Forms.Application.ThreadContext.DisposeThreadWindows()

I try to do Application.DoEvents() before changing the split type but it still happens.

Dan