Thanks for the feedback, I will fix it.
You can make SQL Workbench use Oracle's dbms_metadata, by setting the configuration property:
workbench.db.oracle.use.dbmsmeta.mview=true
Or if you want it for all Oracle objects (Tables, Views, Index, etc)
workbench.db.oracle.use.dbmsmeta=true
You can set this e.g. using WbSetConfig or by editing workbench.settings.
Regards
Thomas