Hi,
We have a new search capability planned for an upcoming release. In the meantime, you could try out the new functionality by turning on "Experimental Features" in Bloom Settings, then activating "Search Experiment" in the new Experimental Features drawer that appears as a beaker icon above the Settings icon.
Generally, the search you describe should work - using the experimental search you can search a specific role by entering the relationship name ACTED_IN followed by tab and the property you want to search, role, then tab again and the value you're searching for. You should also be able to use a full text search for the value, if it is indexed. Another more advanced option would be to create a Search Phrase in Bloom by writing a parameterized Cypher statement to find specific roles. More information about Search Phrases can be found here.