With my JTree I get some blank lines and not correctly drawn selection boxes. I observed the same behavior when modifying the model from a different thread then the EDT in the past.
Furthermore, these glitches seem to come at random. I was monitoring every TreeModelEvent with a separate listener and writing them to an output.
When I noticed this glitch I restarted the application and repeated all steps from the previous run in the exact order. The same glitch did not appear at the same time, but sometimes earlier and sometimes later.
This is another reason why I was thinking that this might be because of events being fired out of sync.