Ok, so it didn't solve my problem, i saw that i have also normalizeScroll enabled on my project, and when it's enabled i'm unable to scroll when modal is open. I tried to make a demo with normalize, i'm not sure should i register it on codepen with gsap (include it in gsap.registerPlugin, cuz i add it it trows an error)? but when it's enabled on codepan it works same as your demo, i'm not sure if it's enabled or i'm doing something wrong