Selecting actor in viewport murders frame rate on mac

I’m getting a solid 70-80 fps in the editor until I select something, at which point the frame rate drops to 20-30. This is on a 2017 15" MBP with an external GTX 1070, running Sierra. This doesn’t happen in 4.18 or earlier versions.

Hello,

We’ve recently made a switch to a new bug reporting method using a more structured form. Please visit the link below for more details and report the issue using the new Bug Submission Form. Feel free to continue to use this thread for community discussion around the issue.

https://forums.unrealengine.com/unreal-engine/announcements-and-releases/1410408-unreal-engine-bug-submission-form

Thanks