[Bug]Some place the second items shows very slow or stagnate

What steps will reproduce the issue?
1. In the java class, right-click, show the menu
2. Now, chose the items up and down by mouse
3. When mouse stop or slide the second item, it show the second item's contents shows very slow or stagnate.

What is the expected result?
It should be show fast and no stagnate.
What happens instead?
The second item's contents very slow or stagnate.
I upload a video (https://youtu.be/srXqjYT9JQg), only 30-50s speed is normal, the other time show the the second item speed is abnormal.

Please attach idea.log (go to Help | Show Log in ... to discover it easily). You can use 'Attach File Privately' item to make attachments visible to 'jetbrains-team' group only. If you don't want to share IDE logs even with JetBrains team please at least paste information about IDE build and your environment below (it can be copied from Help | About dialog).

Сonsider attaching a screenshot, screencast, or a code sample when it's hard to articulate the problem. Note that you can easily drag & drop files of any type into the issue.

If you are experiencing performance issues, please also [attach the snapshots](https://intellij-support.jetbrains.com/hc/en-us/articles/207241235).