Use a 1080p monitor. This issue seems to be related to the DPI of the Macbook Pro built-in retina display, or any monitor with a high enough DPI. So 1080p is recommended.
Lower the scaling of your Built-in retina display. Under macOS Settings → Display → Resolution: Scaled
This solution isn’t perfect though, and there is still some lag but not as much.
This was a tough problem to solve and went through multiple rounds of discussion within the company. We finally think we fixed some issues by backporting a patch from Qt 5.9. This will be going out early next year.
Please make sure you’re running the latest Studio (0.345+) as last Wednesday we’ve deployed a fix for this exact issue. If you’re on the latest, can you please confirm you’re still able to repro it?
Tried it out on a similar machine, but don’t see any issues. First of all, I agree with EchoRepear, this is a different problem. Second it may be specific to your machine or your place. Please try it out on a different PC, different place. If the problem reproduces post a bug, PM me your place.
I’ve started experiencing this issue in the last few weeks as well. It’s not only with editor but doing anything in studio causes it to lag for a few seconds, even something as simple as clicking something in Workspace.
I have a PC/Windows computer that does not have the same issue, but it is still annoying to have to switch between the two.
I’ve reinstalled ROBLOX, deleted all my plugins, updated my flash player and OS, everything… nothing fixes the issue.
This is probably a different issue since the one reported in the OP has been fixed. Please file a new report, and make sure to include all information requested in How to post a Bug Report