Marking an entry "Unread" after it is edited
When you allow users to edit an entry, you may want to mark it as "Unread" so that you can re-review the changes made. If you want to do this, you can install this plugin: GravityView Mod: Mark Entry Unread After Edit
After installing and activating that plugin, when you edit an entry in GravityView, it will be marked as unread in Gravity Forms.
Alternative ways to accomplish this without custom code
GravityView has a setting in the Edit Entry tab named "Unapprove Entries After Edit". Enabling this feature will allow you to filter by Unapproved entries and quickly review all unapproved entries.
Since this is built-in functionality, we recommend this method.