As in UML Sequence Diagram some of the objects are represented as vertical dashed lines, have their name displayed at the top of this line (lifelines). Such objects also have a rectangle on top of the line showing the activation of the lifeline. Is it possible to resize this rectangle on top of the object without changing object's size itself? The implementation already includes GraphRep TABLE to keep this rectangle proportional and allow only height, not width, adjustments to the object.