GSX BY DEFAULT, automatically calculates the marshaller position based on your actual eye point position in the cockpit compared to the Stop position on ground, they both interacts.
You can of course change this, either with the Max marshaller distance, which still result in an automatic calculation but UP to a maximum value, or you can just place the marshaller manually, which means it will *always* stay there, regardless of the airplane.
If you place the marshaller as close as possible to the terminal, and this still result in the ladder, maybe the problem is not the marshaller, but it's the Stop position that is too close, because the ladder is shown because GSX has calculated you won't be able to see the marshaller so, obviously, better a marshaller on a ladder ( which IS used in real world in some cases ), that a marshaller you cannot see.
If you think there's plenty of space to have a marshaller on ground and still be visible, check the Stop position. The AFCAD might not have been done correct and, the AFCAD system is anyway too limited to have a proper Stop position that would work with different airplanes, so I suggest reading the chapter named "Understanding the Stop Position at Page 43 of the GSX manual, no need to repeat it here but, in general, it's the combination between the Marshaller position, the Stop position and your eyepoint in the cockpit, which will affect the presence of a ladder.
Since you WANT to have the Stop position set up correctly, for so many other reason than just the marshaller on ladder or not ( visual safegates, jetway solution, etc. ), it's best to adjust that, rather than having a disable ladder option which would only hide what is really a problem with the Stop position. If you set the Marshaller and the Stop position correctly, you'll see a ladder will be used probably only in a situation that it would also be used in real life.
