Hi,
There was an err file but it had been created 2 months ago, so I deleted the file in order to have a new one created.
(It contained errors for airport LFLB which I didn't use for testing the 777 with GSX and 2 months ago I didn't have the 777 anyway)
Before starting P3D, I installed the latest version of GSX, released yesterday.
After starting P3D and at FlyTampa EKCH, no new error file was created.
I have mapped Ctrl-Shft-F12 to open the GSX window and double checked all 777 keymappings in the FMC for conflicting mappings.
There was none.
Also Ctrl-F12, the common 'YouControl' menu mapping in Couatl key mapping window doesn't function in 777.
Here are 2 images, at FlyTampa EKCH gate C33 (also tried other gates)
With NGX full menu, with 777 no menu at all.
NGX
777