Sequence InteractionFragmet postioning

[Jan Novák]

Hi all,

Im developing sequence diagram generator from C# source code. (in C#) Im already able to generate lifelines, messages and combined fragments to diagram. But im having troubles with positioning elements on diagram. Messages, when proper SequenceID is set, are positioned in Y direction automaticaly and x position of lifelines is not a problem. But I need to place Fragments (e.g. loops, alts and so) over right messages.

Is there any possibility to link messages and proper partitions of Combined fragments and then let EA to set positition of fragments automaticaly?
Or is it better way to get positions of messages automaticaly set by EA and then calculate right position of fragments?
Or do I have to calculate all positions of all elements in diagram in my code?
What do you think is the best approach?

I will be wery grateful for ANY suggestion!
It is part of my barcelor final work and I spent few days by experimenting and searching for solution, but my results are wery poor.  

[Jan Novák]

I found some wierd behavior of connectors:

If I add a connector, in StartPointY, EndPointY properties is 0. If I try to set some value to this property, when diagram is opened in EA, nothing happend, value is still same, and at diagram is connector at the same place.
But if I move connector in EA by mouse and save diagram, value of properties is changed and it is not possible to change value.
Im calling update() after each operation...

Does anybody know the reason of this behavior?