j and k scrolling doesn't work on reddit

[sooriravindra]

Google Chrome : 73.0.3683.103 (Official Build) (64-bit) (cohort: Stable)
OS : Windows 10 OS Build 17134.706

Scrolling on reddit posts doesn't work as expected. j and k scroll the background instead of the pop up post. There seems to be a PR #3119 already merged for this issue before. Seems to be a regression.

[philc]

This should be fixed by #3327.