1. register hudson instance -> eg. http://deadlock.netbeans.org/hudson
2. status icon shows a couple of failed builds (if any exists)
3. remove this instance
=> status icon still shows failed builds from hudson instance which is not registered with netbeans anymore
True, these should be cancelled. Probably an unusual and low-priority problem.
BTW good to know you are testing this!
No time for 6.7.
Did not make it for 6.8.