When working in the schema browser and clicking on the data tab, Toad hangs. Other tabs come up without problems and is only an issue with the data tab. This is an issue with most tables but not all, and can occur with any connection. This a problem for multiple users and installs. Data can still be queried from the table itself manually in the editor. The session is not cut off in SQL Plus like in Toad.
Firewall restriction cutting off the session when "SELECT ROWID, <columns> FROM <user.table>" is run by Toad to gather records for the data tab.
Disable or adjust firewall on the network to stop from cutting off database connections.