How do I know if someone else is editing a backlog item?

[Stuart Rosen]

We're new to VersionOne and have run into an editing issue. We've found that if Person A is editing a backlog item, Person B can open the edit screen for that item, make changes, and click Save, but the changes won't be saved because Person A is in edit mode. Is there a way to tell that someone else has their edit screen open? Or, is there a way to lock the item while editing so other people aren't able to open the edit screen?