A long expression that indicates the key of the shape being removed.
Use the RemoveShapeCorner property to remove a shape corner
being added using the AddShapeCorner method. Use the StartShape and EndShape
properties to define the start and end parts of the bar using custom shapes. Use the Images or ReplaceIcon
method to update the list of control's icons. The control includes a list of predefined
shapes like shown in the ShapeCornerEnum