There is still an issue with installing the DFGT sometimes, windows likes to pick it up as the DFP and some of the buttons don't work regardless of driver version.
What you need to do is completely remove the drivers, with the wheel unplugged. Then reinstall the drivers and only plug the wheel in when it asks you, making sure the power and pedals are also connected. That should allow the logitec drivers to detect it as a DFGT instead of the default DFP setting windows uses.
I had issues with this when I first got my DFGT.