Crash changing guard in StateMachineDiagram (#187)
System.ArgumentOutOfRangeException: Length cannot be less than zero.
Parameter name: length
at System.String.InternalSubStringWithChecks(Int32 startIndex, Int32 length, Boolean fAlwaysCopy)
at SoftwareIdeasModeler.Core.DiagramItems.UmlObjects.ConcreteUmlTransition.SetTransitionText(String value)
at SoftwareIdeasModeler.Core.DiagramItems.UmlObjects.ConcreteUmlTransition.SetField(DiagramItemField field, String newValue)
at SoftwareIdeasModeler.Core.Commands.SetEditFieldCommand.Execute()
at SoftwareIdeasModeler.Core.Projecting.CommandStack.AddCommand(Command command, Boolean execute)
at SoftwareIdeasModeler.Core.Projecting.Project.Execute(Command cmd)
at SoftwareIdeasModeler.SimDiagramControl.ConfirmEditing(Boolean editNext)
at System.Windows.Forms.Control.ProcessKeyEventArgs(Message& m)
at System.Windows.Forms.Control.WmKeyChar(Message& m)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)