That is caused by the "vidbar" extension.

Are you running the latest version of the extension? If you are, please contact the extension author

Hi,

I was having the exact same problem while browsing some sites (Google news, Google image search, Youtube).

It was caused by the "Screenshot Pimp" extension. I uninstalled it and all is OK now.

It looks like this extension packs a lot of "generic" code that is not used by the extension but could be used by other extensions from the same publisher (Mediapimp).

So if you have this extension try removing it (not just disabling it). If you don't, look for other extensions like viddownloader, Youtube downloader, Video downloader, Mediapimp, etc. and remove them one by one until your browser is back to normal.