public override void MouseDown(NSEvent theEvent)
        {
            NSPoint locationInSelf = this.ConvertPointFromView (theEvent.LocationInWindow, null);
            NSRect dragThumbFrame = this.dragThumbView.Frame;

            if (dragThumbFrame.PointInRect (locationInSelf)) {
                this.dragOffsetIntoGrowBox = new NSSize (locationInSelf.x - dragThumbFrame.origin.x, locationInSelf.y - dragThumbFrame.origin.y);
                NSDictionary metrics = NSDictionary.DictionaryWithObjectsAndKeys (
                NSNumber.NumberWithFloat (dragThumbFrame.MinX), (NSString)"initialThumbX",
                NSNumber.NumberWithFloat (dragThumbFrame.MinY), (NSString)"initialThumbY",
                null);
                NSDictionary views = NSDictionary.DictionaryWithObjectForKey (this.dragThumbView, (NSString)"dragThumbView");

                this.horizontalDragConstraint = NSLayoutConstraint.ConstraintsWithVisualFormatOptionsMetricsViews ("H:|-(initialThumbX)-[dragThumbView]", 0, metrics, views).LastObject.Retain<NSLayoutConstraint> ();
                this.verticalDragConstraint = NSLayoutConstraint.ConstraintsWithVisualFormatOptionsMetricsViews ("V:|-(initialThumbY)-[dragThumbView]", 0, metrics, views).LastObject.Retain<NSLayoutConstraint> ();

                // try lowering the priority to NSLayoutPriorityDragThatCannotResizeWindow to see the difference
                this.horizontalDragConstraint.Priority = NSLayoutPriority.NSLayoutPriorityDragThatCanResizeWindow;
                this.verticalDragConstraint.Priority = NSLayoutPriority.NSLayoutPriorityDragThatCanResizeWindow;

                this.AddConstraint (this.horizontalDragConstraint);
                this.AddConstraint (this.verticalDragConstraint);

                // just for fun.  Try it out!
                this.Window.VisualizeConstraints (NSArray.ArrayWithObjects (this.horizontalDragConstraint, this.verticalDragConstraint, null));
            }
        }

		void HandleKeyAction (NSEvent theEvent, bool isUp)
		{
			ulong code = DecodeFromUnicode (theEvent.Characters);
			NSKey keyPressed;

			if (code == 32)
				keyPressed = NSKey.Space;
			else if (code == 114)
				keyPressed = NSKey.R;
			else
				keyPressed = (NSKey)DecodeFromUnicode (theEvent.Characters);

			switch (keyPressed) {
			case NSKey.RightArrow:
				UpdateKey (RightKey, isUp);
				break;
			case NSKey.LeftArrow:
				UpdateKey (LeftKey, isUp);
				break;
			case NSKey.R:
				UpdateKey (RunKey, isUp);
				break;
			case NSKey.Space:
				UpdateKey (JumpKey, isUp);
				break;
			default:
				break;
			}
		}

		public static MouseButtons GetMouseButtons (NSEvent theEvent)
		{
			MouseButtons buttons = MouseButtons.None;
			
			switch (theEvent.Type)
			{
			case NSEventType.LeftMouseUp:
			case NSEventType.LeftMouseDown:
			case NSEventType.LeftMouseDragged:
				if ((theEvent.ModifierFlags & NSEventModifierMask.ControlKeyMask) > 0)
					buttons |= MouseButtons.Alternate;
				else
					buttons |= MouseButtons.Primary;
				break;
			case NSEventType.RightMouseUp:
			case NSEventType.RightMouseDown:
			case NSEventType.RightMouseDragged:
				buttons |= MouseButtons.Alternate;
				break;
			case NSEventType.OtherMouseUp:
			case NSEventType.OtherMouseDown:
			case NSEventType.OtherMouseDragged:
				buttons |= MouseButtons.Middle;
				break;
			}
			return buttons;
		}

		public static Point GetLocation (NSView view, NSEvent theEvent)
		{
			var loc = view.ConvertPointFromView (theEvent.LocationInWindow, null);
			if (!view.IsFlipped)
				loc.Y = view.Frame.Height - loc.Y;
			return Generator.ConvertF (loc);
		}

 //Handle right click event for the TableView
 public override NSMenu MenuForEvent (NSEvent theEvent)
 {
     CGPoint pt = this.ConvertPointFromView (theEvent.LocationInWindow, null);
     _selectedRow = this.GetRow (pt);
     NSTableViewDataSource ds = (NSTableViewDataSource)this.DataSource;
     NSMenu menu = new NSMenu ();
     if (_selectedRow >= (nint)0) {
         if (ds is NodesListView) {
             DirectoryNode node = ((ds as NodesListView).Entries [(int)_selectedRow] as DirectoryNode);
             if (node != null) {
                 if (node.NodeType == DirectoryNode.DirectoryNodeType.User) {
                     NSMenuItem ResetPassword = new NSMenuItem ("Set Password", node.RestUserPassword); 
                     menu.AddItem (ResetPassword);
                     NSMenuItem delete = new NSMenuItem ("Delete", node.Delete); 
                     menu.AddItem (delete);
                     NSMenuItem Properties = new NSMenuItem ("Properties", node.ViewProperties); 
                     menu.AddItem (Properties);
                 } else if (node.NodeType == DirectoryNode.DirectoryNodeType.Groups) {
                     NSMenuItem addUser = new NSMenuItem ("Add user to group", node.AddUserToGroup); 
                     menu.AddItem (addUser);
                 }
                
             }
         }
     }
     NSMenu.PopUpContextMenu (menu, theEvent, theEvent.Window.ContentView);
     return base.MenuForEvent (theEvent);
 }

        public void ExtendSelection(NSTextView view, NSEvent evt)
        {
            int index = DoMouseEventToIndex(view, evt);

            NSRange range = view.selectedRange();
            if (range.length == 0 && index < view.string_().length() && view.string_()[index] == '\n')
            {
                // don't extend the selection if the user clicked off to the right side of a line
            }
            else if (index >= view.string_().length())
            {
                // don't extend the selection if the user clicked below the last line of text
                view.setSelectedRange(NSRange.Empty);
            }
            else
            {
                // Extend the selection so that it contains the entire word the user right-clicked on.
                if (range.length == 0 || !range.Intersects(index))
                {
                    range = new NSRange(index, 1);
                    range = view.selectionRangeForProposedRange_granularity(range, Enums.NSSelectByWord);
                    view.setSelectedRange(range);
                }
            }
        }

		public override void SwipeWithEvent (NSEvent theEvent)
		{
			// We are only interested in horizontal swipe
			if (theEvent.DeltaX == 0)
				return;
			FireSwipeEvent (theEvent.DeltaX > 0 ? SwipeSide.Left : SwipeSide.Right);
		}

		public override void MouseMoved (NSEvent theEvent)
		{
			if(theEvent == null)
				return;
			base.MouseMoved (theEvent);
			FireMouseMoved (theEvent);
		}

		public override void MouseDragged (NSEvent theEvent)
		{
			PointF point = this.ConvertPointFromView (theEvent.LocationInWindow, null);
			this.Host.FireMouseMove (Host, new MouseEventArgs (MouseButtons.Left, theEvent.ClickCount, (int)point.X, (int)point.Y, 0));
			
			base.MouseDragged (theEvent);
		}

		public override void RightMouseUp (NSEvent theEvent)
		{
			if(theEvent == null)
				return;
			base.RightMouseUp (theEvent);
			FireRightMouseUp(theEvent);
		}

		public override void RightMouseDragged (NSEvent theEvent)
		{
			if(theEvent == null)
				return;
			base.RightMouseDragged (theEvent);
			RightMouseDragged (theEvent);
		}

		public override void MouseButtonUp (NSEvent theEvent)
		{
			PointF ui_pt = ParentScreen.ScreenToLayer (theEvent.LocationInWindow);
			
			if (PointInside (ui_pt))
				OnActivate ();
		}

		public void KeyboardDown (NSEvent theEvent)
		{
			bool selection_changed = false;

			/* navigation keys */
			if (theEvent.CharactersIgnoringModifiers[0] == (char)NSKey.UpArrow) {
				if (cursor > 0) {
					cursor--;
					selection_changed = true;

					if (cursor < first_visible)
						first_visible = cursor;
				}
			}
			else if (theEvent.CharactersIgnoringModifiers[0] == (char)NSKey.DownArrow) {
				if (cursor < items.Count - 1) {
					cursor++;
					selection_changed = true;

					if (cursor >= first_visible + num_visible)
						first_visible = cursor - num_visible + 1;
				}
			}

			if (selection_changed) {
				Invalidate ();
				if (SelectionChanged != null)
					SelectionChanged (cursor);
			}
		}

		public override void MouseUp (NSEvent theEvent)
		{
			if(theEvent == null)
				return;
			//base.MouseUp (theEvent);
			m_parent.HandleClick(theEvent.ClickCount,new MouseEventArgs(MouseButtons.Left,theEvent.ClickCount,theEvent.AbsoluteX,theEvent.AbsoluteY,theEvent.AbsoluteZ));
		}	

		public override NSMenu menuForEvent(NSEvent @event)
		{
			if (menu == null)
				return base.menuForEvent(@event);
				
			//  NSLog(@"menuForEvent:");
			//  Find which row is under the cursor
			this.window().makeFirstResponder(this);
			NSPoint menuPoint = this.convertPoint(@event.locationInWindow()) fromView(null);
			int row = this.rowAtPoint(menuPoint);
			if (row > -1)
			{
				bool currentRowIsSelected = this.selectedRowIndexes().containsIndex(row);
				if (!currentRowIsSelected)
					this.selectRowIndexes(NSIndexSet.indexSetWithIndex(row)) byExtendingSelection(false);
			}
			else
			{
				this.deselectAll(null);
			}
			if (this.numberOfSelectedRows() <= 0)
			{
				//  No rows are selected, so the table should be displayed with all items disabled
				NSMenu tableViewMenu = this.menu().copy();
				for (int i = 0; i < tableViewMenu.numberOfItems; i++)
					tableViewMenu.itemAtIndex(i).setEnabled(false);
				return tableViewMenu;
			}
			else
				return this.menu();
		}

		public override void MouseMoved (NSEvent theEvent)
		{
			if(theEvent == null)
				return;
			PointF point = theEvent.LocationInWindow;
			this.Host.FireMouseMove (Host, new MouseEventArgs (MouseButtons.Left, theEvent.ClickCount, (int)point.X, (int)point.Y, 0));
			//base.MouseMoved (theEvent);
		}

		public override void MouseUp (NSEvent theEvent)
		{
			PointF point = this.ConvertPointFromView (theEvent.LocationInWindow, null);
			
			var button = (MouseButtons)theEvent.ButtonNumber;
			this.Host.FireMouseUp (Host, new MouseEventArgs (button, theEvent.ClickCount, (int)point.X, (int)point.Y, 0));
			base.MouseUp (theEvent);
		}

		public override void MouseUp (NSEvent theEvent)
		{
			var skScene = (InGameScene)OverlayScene;
			CGPoint p = skScene.ConvertPointFromView (theEvent.LocationInWindow);
			skScene.TouchUpAtPoint (p);

			base.MouseUp (theEvent);
		}

		public override void KeyDown (NSEvent theEvent)
		{
			if ((NSKey)(theEvent.Characters [0]) == NSKey.RightArrow)
				right ();
			else if (theEvent.Characters [0] == 'r')
				reset ();
			else
				base.KeyDown (theEvent);
		}

		public override void KeyDown (NSEvent theEvent)
		{
			if ((NSKey)theEvent.KeyCode == NSKey.RightArrow)
				right ();
			else if ((NSKey)theEvent.KeyCode == NSKey.R)
				reset ();
			else
				base.KeyDown (theEvent);
		}