I am running a 4K monitor and my early-2013 Retina MacBook Pro laptop can only do 4K@30Hz

At this resolution the interface in pico8 is mostly unresponsive. For example clicking a colour to change the selected colour in the graphics mode, or clicking a menu bar icon to change mode, just do not work reliably.

here i am clicking like mad to get things to change:
https://youtu.be/nvdamx19JoY

However, if I switch the resolution to 1080p@60Hz then every click is registered as expected.

Let me know if I can provide any debugging info.

pico8 v0.1.11g
macOS 10.13.2 (17C205)
Dell P1415Q

Your and my bugs may be related:

https://www.lexaloffle.com/bbs/?pid=48103#p48103

I don't think PICO-8 runs well at anything other than 60Hz refresh, even when it should be possible to sync cleanly.

@Felice yep, I think this is effectively the same issue

it's gotta Hertz

(sorry)

I can tolerate puns, as long as their frequency is low.

hahaha