So, yesterday I tried dispatching a flight without an APU. Since it's an airliner, it will start with the aid of a GPU and Air Starter. So, before anything else, I went and selected the option to start engines before pushback in the airplane config and saved.
Now with ASU and GPU connected, I request pushback. GSX is now on hold, waiting for the GPU to disconnect. In other words, the push sequence does not start. I decide to start the engine on GPU and the request push. GSX says nope. The engine needs to be off for the sequence to start. In the end I had to shut down the engine, fix the APU and push back because I could find a way to use GSX when an APU is inoperative and you want to start on GPU before push.
Did I miss something? Maybe an additional setting that bypasses all these checks?
Thanks,