If the only thing you are missing are the marshaller distance readout, it's because you disabled it in the GSX Settings.
If, instead, you are missing other things, like jetway numbers, jetway logos, fuel counters, it's because you have enabled the "Disable RTT" option in the Addon Manager, which removes every text-based feature in the program, and should be used only in very specific case of incompatibility with video drivers ( for example, in SLI configurations ).
