Error when clicking to create new Class Diagram for existing project (#399)

Please fix the following error, which I received, when I clicked to create a new Class Diagram for my existing project (I am on Version 8 of Software Ideas Modeler Professional):

System.ArgumentException: Rectangle '{X=0,Y=0,Width=0,Height=0}' cannot have a width or height equal to 0.

at System.Drawing.Drawing2D.LinearGradientBrush..ctor(Rectangle rect, Color color1, Color color2, LinearGradientMode linearGradientMode)

at SoftwareIdeasModeler.SimDiagramControl.DrawDiagramBackground(IGraphics g, BackgroundType backgroundType, Color color1, Color color2, Rectangle bounds)

at SoftwareIdeasModeler.SimDiagramControl.DrawPaper(DiagramDrawer drawer)

at SoftwareIdeasModeler.SimDiagramControl.canvas_Paint(Object sender, PaintEventArgs e)

at System.Windows.Forms.Control.PaintWithErrorHandling(PaintEventArgs e, Int16 layer)

at System.Windows.Forms.Control.WmPaint(Message& m)

at System.Windows.Forms.Control.WndProc(Message& m)

at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

Also, I receive an error, when I try to use the supplied dialog to "Send" a message to Software Ideas Modeler.