Oh. This will be a lot of fun...
I have not really used FM3 in Save/Load dialog so I never noticed there was such an issue. I do remember that back when FM2 was used, it works. Although that was written with AutoHotkey. Almost all the time, I use FM3 to launch applications and certain scripts.
Sorry but unfortunately I don't have the time now to work on this much but if I do figure something out, I will definitely post it here.