Currently, URL Parameter is only available to add to a Trigger. While this should remain there, URL Parameter should also be added under Segment creation criteria. This is for use cases where we are trying to expose dynamic content to a specific marketing group (i.e., users that came from our "new arrivals" email). Typically this audience is too small, so we also want to layer on the segment criteria for "Page Views" for users who frequently view new arrivals / new in pages. However - there is NO way to do this in one campaign, meaning we have to create two campaigns with the same exact creative and then prioritize them, which is not ideal.