Can't see tables in 6.5 oracle 11G

We just upgraded to oracle 11G and on some of our very large schemas we are not able to see the database objects. For instance when clicking on the plus sign on the tables nav will popup an hour glass, then just go blank.

The hour glass goes away but we are not able to drill down to the tables. My schema has 831 tables but this should not be a problem. We are able to see the tables in sys which has over 900 tables.

HELP

Hi Henry,

You meant you are using 11gR2 database right?

If you are, this is a known issue in 11gR2 DB when there are external tables in your list(CR13550), we have fixed it already in 6.6beta.

If you don’t mind, the latest beta build(6.6.0.2220) is on the following page in community:
http://sqlnavigator.inside.quest.com/thread.jspa?threadID=33919&tstart=15

Thanks and best regards,
Shirly