MonoHotDraw.Tools.DragTool.MouseDown C# (CSharp) Method

        public override void MouseDown(MouseEvent ev)
        {
            base.MouseDown (ev);
            IDrawingView view = ev.View;

            SetLastCoords (ev.X, ev.Y);

            Gdk.ModifierType state = (ev.GdkEvent as EventButton).State;

            bool shift_pressed = (state & ModifierType.ShiftMask) != 0;

            if (shift_pressed) {
                view.ToggleSelection (AnchorFigure);
            }

            else if (!view.IsFigureSelected (AnchorFigure)) {
                view.ClearSelection ();
                view.AddToSelection (AnchorFigure);
            }
            CreateUndoActivity();
        }