I've recently upgraded to version 1.1.383 which has some really nice new features! However in my .Rmd scripts the grayish highlighting is now completely messed up (as shown i the attached picture). Sometimes it's there, sometimes only a few lines within the chunk are highlighted sometimes only the first line of the chunk is highlighted etc..
Additionally the green arrows to run a whole chunk sometimes disappear.
OS: Linux Mint 18.2 based on Ubuntu 16.04