EDIT: As of FogBugz 8.8, you can add release notes at any time.
Many times I create a case, and at that time, I already have the release notes in mind. In our last process using StarTeam, we had a custom field for the release notes and I almost always added what I wanted the release note to say when I created the case. I typically only use the release note text and not the case description, so I can create something like "The system now supports X" when I have a case that is "Implement X". It would be beneficial to me to have the release notes link visible at ALL times and not just when an item has been resolved.
We use FogBugz extensively and need the ability to edit the Release Notes prior to a case being resolved or closed in order to better coordinate with our internal support and training staff, as well as with our existing customers. We routinely share our Release Notes ahead of the actual release to give our clients the opportunity to become familiar with the functionality and configuration choices. The current Release Notes feature does not support editing prior to resolution of a case which prohibits us from fully utilizing the power of FB!
We are using the Release Notes field after a case is Resolved. Sometimes, a developer would like to add Release Notes before it is Resolved. For example, the Backend Developer is ready, adds the Release Notes, assignes the Active case to a Frontend Developer and the Frontend Developer Resolves the case and adds more Release Notes.