That's a good point. More experiments:Disabled all patches. Restarted services. Apps behave as expected. Started enabling patches one by one. So far so good. Bingo! Got the culprit. "Eventview controls attached page". Disable the patch, restart lipstick, no problems. Enable patch, restart lipstick, 100% reproducibility. Still present in 1.1.4.29, but that is hardly surprising.