When adding a Has Opportunity filter, which is based upon a Salesforce Contact's relationship to Opportunities via Contact Roles, the "Role" field is not available. Please make that be an available filter constraint.
We would use the "Was Added to Opportunity" filter, but that is only based upon the "Added to Opportunity" trigger firing. For a new Marketo customer (us), that makes this Filter unusable for a little while. That filter actually has "Role" as a Constraint option! Thus, the need for the Has Opportunity filter to include Role.
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