Arc Catalog Maintains locks unnecessarily

I do not understand why Arc Catalogue maintains a lock
on any layer or dataset that it has ever visited.
The user only has to click such an entity and
preview it for ArcCatalogu to maintain a lock
on the entity for the duration of its invocation.

This isn't just an academic point. It seems that these locks
can often interfere with other operations one is trying
to accomplist... in ArcGIS Desktop for instance.