This feature would be needed to change the caller or the callee after drawing a message between them with numerous parameters. The only way I could do this is to copy the list of parameters, delete the message and draw a new message correctly then choose/enter message and paste parameters. The quick and comfortable way for this in my opinion would be to drag an end of the arrow and have it stick to the desired lifeline.
This scenario is common when changing the level of abstraction, i.e. inserting additional entities or removing entities from a sequence diagram.
I guess reattaching the end with the arrowhead (changing callee) would be more complicated as the new callee might not have an operation with the same name. The message name could be treated as if it would have been entered manually or a dialogue could show up. While changing the caller (reattaching the opposite end of the arrow) should be simpler.
I think this could even be generalized for any relation/transition/flow in any diagram.
I realize the early stage of this project and that new features will only be considered after the port is complete and the code base is more or less stable, just registering this so it does not get lost. The feature has been requested in the original BoUML project but has never been implemented.
Thanks!
