dbca 'delete a database' option greyed out on 11gR2 Exadata after upgrade from 11.2.0.3 to 11.2.0.4

Hi there

I have upgrade a exadata machine, the grid + ASM  from 11.2.0.3 to 11.2..0.4

I have also upgraded some databases from 11.2.0.3 to 11.2.0.4.

I need to drop a database which is not update to 11.2.0.4

When i start dbca, from OH 11.2.0.3,  the 'Delete database" option is not available.

When i start dbca, from OH 11.2.0.4 the 'Delete database" option is available but the database is not in the list.

I know that i can drop manually the database, but i prefer to use the dbca

Any ideas?

thanks in advance