windows 10 hidden extensions hides dropdown entries

[Azaezel]

Entirely possible it's something we overlooked in our roll in, but had a couple users report an inability to see file type selectors in windows 10. We traced it down to them having flipped on 'hide extensions for known file types' in conjunction with https://github.com/mlabbe/nativefiledialog/blob/master/src/nfd_win.cpp#L186

cooked up a quickiepatch our end https://github.com/GarageGames/Torque3D/pull/2270/files. would you like a similar one, or would you prefer to handle it a different way?

[mlabbe]

Fixed in ad50d4f.