Allright, author of MyContacts answered here: http://talk.maemo.org/showpost.php?p...&postcount=461

Probably there is a way to not stop MyContacts but to just close all open windows? In case this really works (not yet tested) this would be a compromise, as MyContacts is quite slow when starting. Will test and report.

Doesn't work too. After restart of desktop it behaved differently from before but in the end it was the same. I could tap on the dialog with the dbus message (e.g. confirm it) but it just re-appeared. So I was left in a loop of dbus messages and then device rebooted by itself. Maybe it would have worked with an earlier version but I just don't have time to get older package files and test them too. So, let's kill all instances of MyContacts and user will have to restart it again, that's OK for me.