public void mouseDown(MouseEvent e, int x, int y) {

		Position position = GfxConstants.getPositionFromXY(x, y);

		if (position.getRow() >= 0
				&& position.getRow() < GameConstants.WORLDSIZE
				&& position.getColumn() >= 0
				&& position.getColumn() < GameConstants.WORLDSIZE) {

			Unit unitAt = game.getUnitAt(GfxConstants.getPositionFromXY(x, y));

			if (unitAt != null && isValidUnitToMove(unitAt)) {
				isDraggingUnit = true;
				draggingFrom = position;

				dragTracker = new DragTracker(editor, editor.drawing()
						.findFigure(x, y));
				dragTracker.mouseDown(e, x, y);
			}
		}
	}