Tested CS757, PMDG 737NGX, PMDG 777 and Aerosoft A320 family. Same results for all - if I make changes in the editor, it works fine for that session and it writes the changes to the file. If I then close and reopen the sim, everything is out of position again BUT the gsx.cfg files do not change - they still reflect the changes I made in the previous session. The only way to get it to work is to delete the respective gsx.cfg and start again. Which sets the whole cycle off again. This is in FSX-SE.