Thank you very much Larry for your reply!
I will try to track down problems I encounter with the JEE Module
Dependencies property page, although it's not that easy because they
usually are difficult to reproduce in an unconditional way.
However, I can state for sure that:
1) we're not sharing entire projects within our team: we just share code
and then assembly it in our own workspace by ourselves. This would open
a huge discussion, however the two main reasons are that not all the
team members use Eclipse and that our webapp is made of many different
modules inter-dependent from each other, so sharing an entire project is
not enough flexible
2) I saw problems even when the workspace started as a new one (not
migrated from a previous version of Eclipse)
Mauro.