Package Diagrama -> Use (#464)

Hi, sometimes when i choose Use command in Package Diagram app crash

System.NullReferenceException: Referencia a objeto no establecida como instancia de un objeto.

en SoftwareIdeasModeler.Core.Projecting.Diagram.GetNearestElementAt(ConcreteRelation activeRelationship, PointF location, Boolean exceptInside, Int32 maxDistance)

en SoftwareIdeasModeler.Canvas.CanvasProcessor.GetEndElementForConnector(Diagram diagram, Point location, ConcreteRelation connector, IConcreteDiagramElement hoverElement, List`1 overElements)

en SoftwareIdeasModeler.Canvas.CanvasProcessor.GetEndElementForConnector(Point location, ConcreteRelation connector, Boolean ignoreOverElements)

en SoftwareIdeasModeler.SimDiagramControl.DrawHotAreas(DiagramDrawer drawer)

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

en System.Windows.Forms.Control.OnPaint(PaintEventArgs e)

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

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

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

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

OF=SoftwareIdeasModeler.MainForm

LastCmd=SoftwareIdeasModeler.Core.Commands.CombinedCommand

OF=SoftwareIdeasModeler.Forms.FolderOverviewForm

OF=SoftwareIdeasModeler.Forms.EditorForm

OF=SoftwareIdeasModeler.Forms.EditorForm

OF=SoftwareIdeasModeler.Forms.EditorForm