is there a leak of "current number of transactions" in jonasAdmin (JOnAS 5) (or what is the correct meaning of this value?)

Hi JOnAS Team,

during our tests with JOnAS 5.1 we found out a strange figure visible in
jonasAdmin:

After some uptime, the value of "Services -> Transaction -> Statistics
-> current number of transactions"  shows e.g. 3 transactions, even if
the server is idle currently
and there is no activity.

looking at "Monitor" Tab, the 3 transactions are also visible and it is
shown that they are  "zombies", several hours or even days old (looking
at the tx "date" information); 
looking at the age of the transaction, it is cleary higher than the
jonas.jtm.timout value configured in jonas properties; the status is
"STATUS_ROLLEDBACK".

When we take the new "jdbc connection leak detector"  into use, we can
clearly see, that no active JDBC connection is shown here.

So somehow it looks like that these open transactions are leaked ---
could that be the case and is there a way to "force a kill" of those?

BTW: we are currently using hibernate "attached" to the JTA transactions
of jonas - probably it has to do sometihng with an hibernate issue?

regards,
HANS