I'm working with IDEA 2018.2, and when I use intellisense/autocomplete, hints dissapears after about 0.5 sec. I use ctrl+space, see hints and I can't even read them all when it's gone.
It all started when I began new project in React Native, in my Java projects everything works fine.
I looked in Settings->Editor->Code Completion and didin't find anything.
Also I can mention that since i began React Native project, on my bottom bar file indexation blinks for a while every 2 sec. (that's another problem for another topic, but it might be connected).
CrazyCoder's solution fixed my problem.
I updated my IntelliJ to newest version (EAP), and it resolved both problem, with blinking indexing and broken intellisense.
Reposting link for community: https://confluence.jetbrains.com/display/IDEADEV/EAP