I needed to add a report file to a GMAT script using the GUI. When I attempted to do this, the context menu never opened on my computer. I'm running the 2018a version of GMAT under Redhat Linux (CENTOS).
A possible work-around might be adding the report file through the script interface. I don't know the correct sequence of commands, however what I'm interested in doing is reporting the mass of fuel in a chemical tank throughout the mission.