Since I work with web viewer(s) I always used the webkit inspector for debugging. I used to activate this hidden feature modifying the preferences via terminal. (Check this for further info )
But in FileMaker 16 Advanced this feature does not work in my OSX system 11.11.6. I don't know if it is linked to my Safari browser version or FileMaker 16 itself.
If you're able to use webkit inspector in Filemaker 16, please tell me the trick.