I experienced the following problem running Windows 8.1 and Construct 2 Release 269 64Bit and nwjs-for-c2-v0-18-1:
My XBox 360 USB controller was only being recognized when I ran the game in "Debug Mode."
I didn't have this problem prior to upgrading to nwjs-for-c2-v0-18-1.
FIX: I upgraded to nwjs-for-c2-v0-18-7 and it seems to be resolved.