I took a look at the GSX settings for the Main Cargo door, Forward Cargo door, and Aft Cargo door, and they are set correctly (see the attached image).

I pretty sure that what is happening, is that GSX has saved a gsx.cfg in C:\Users\<YourUserName>\AppData\Roaming\Virtuali\Airplanes\CS_B757-200SF-III_RB535E4, and it's reading that gsx.cfg, and not the one you placed in the <FlightSimulator>\SimObjects\Airplanes\CS_B757-200SF-III_RB535E4.

You need to either copy the gsx from <FlightSimulator>\SimObjects\Airplanes\CS_B757-200SF-III_RB535E4 over to C:\Users\<YourUserName>\AppData\Roaming\Virtuali\Airplanes\CS_B757-200SF-III_RB535E4, and overwrite that one.

Or... You can simoply delete the gsx.cfg in C:\Users\<YourUserName>\AppData\Roaming\Virtuali\Airplanes\CS_B757-200SF-III_RB535E4, and then GSX will read the one that you extracted to <FlightSimulator>\SimObjects\Airplanes\CS_B757-200SF-III_RB535E4

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