Disable a panel - but some contents still render. Bug, or feature?

I unchecked the checkbox in the Inspector next to a Panel's name, expecting that this would hide the entire panel. This appears to work in Edit Mode, with the panel and all contents disappearing. But I enter Play Mode and at least one element rendered, a row of data instantiated from a prefab containing various text elements.

Another bug is that after it has been rendered on-screen during Play Mode, that row is visible again in Edit Mode; one of several instances I've found with the new UI where layout changes leak out across modes.

 

Sounds like a bug. Please file a bug report with repro project attached and description of steps to reproduce the problem. Thanks!

 

Case 630943. Seems to want to render things that are unchanged copies of prefab, even when one of its parents are disabled.