Since a couple of weeks, syntax colouring and inspections sometimes don't update correctly in CoffeeScript (WebStorm 2017.1).
Please see image for an example. In that case I commented lines 80-115 but some words remain in their previous colour. Same thing happens with code inspections, e.g. the red underline indicating a syntax error will "stick" even after the error is fixed.
It happens several times an hour. Sometimes the issues resolves itself after a few seconds to a few minutes, otherwise I have to cut then re-paste the code to get the right colouring. (Clicking / Scrolling / Saving / Closing file / etc. don't do anything).