IDEA is very very slow using Scala

Since the other thread was closed without letting me respond I will start a new thread. In the other thread their was a disgruntled user who I thought was a little silly for being so angry. But now I think I am beginning to understand his frustration. 

From https://intellij-support.jetbrains.com/hc/en-us/community/posts/203378724-IDEA-is-very-very-slow :

"JetBrains addresses many performance problems if they are reported properly. For this specific thread the original reporter didn't provide us any data that would help to understand and fix it. It also doesn't mean that your problem is the same as the problem of the topic starter."

Here are some examples where the data was reported: 

https://intellij-support.jetbrains.com/hc/en-us/community/posts/115000115470-scala-editor-very-very-slow?input_string=IDEA%20is%20very%20very%20slow%20using%20Scala

https://youtrack.jetbrains.com/issue/IDEA-160796

https://youtrack.jetbrains.com/issue/IDEA-127440

https://youtrack.jetbrains.com/issue/IDEA-150463

I will try and get a report in, but this seems to be a widespread issue that hasn't been addressed. And closing the topics doesn't seem to help.