Sometimes it's desirable to keep all PD rows visible, not just the rows that have content visible on-screen. There should be an option for this in the settings dialog.
*** Bug 1083 has been marked as a duplicate of this bug. ***
Fixed in ab185f78707eb2800c8b9ea577412ea5f6319f22, thanks!
Additional fix in f994f496908ed183c951ada303c4ba8d18b80b64, thanks!