It takes a few minutes to view locks on the Oracle 10g database. I have changed the optimizer hints for oracle 10g from RULE to CHOOSE or FIRST ROW but this does not seem to make a difference. These few minutes seem very long when resolving locks on the database and the users are waiting.
Fixed in version 9.0. Outer join added in Toad 9.0 which speeds this up a bit when viewing locks in Session Browser. The latest version of Toad for Oracle can be downloaded at: http://support.quest.com/support_download/Downloads.asp