1. Create a new Openshift application for example: jboss
2. nested postgresql-8.4 to the application or nested mysql-5.1 to the application
3. Edit the application and select mysql-5.1 or postgresql-8.4 from the embeddable cartridge and click 'Finish'.

Actual Result:
It will popup "problem occured" dialog...

Expect Result:
it should popup "warning dialog" said that "Only 1 embedded database type permitted - application currently has 'postgresql' or 'mysql' "