It's mostly a browser issue, you can't do much do on the backend side to prevent loosing form data. Mozilla and Firebird are very cooperative regarding that.
Donate to UBBDev today to help aid in Operational, Server and Script Maintenance, and Development costs.
Please also see our parent organization VNC Web Services if you're in the need of a new UBB.threads Install or Upgrade, Site/Server Migrations, or Security and Coding Services.