Attempting to view list of tables in Schema Browser. However, Schema Browser is blank on both sides.
The correct schema was not selected from the Schema drop down.
Background query against sys.user_All_tables view results in no rows.
Schema Browser uses the sys.user_All_tables view to show the list of tables in schema and sys.user_objects view to list Views and Synonyms. Schema Browser defaults to the schema that was logged on as when it is opened initially. Change the schema from the Schema drop down in order view tables from the desired schema or run a query against sys.user_All_tables view in Toad Editor window to confirm number of rows returned.
For more information about sys.user_All_tables view consult with DBA.