add this when opening the modal:
if (context.browser?.["environment"] != "editor") {
wwLib.getFrontDocument().body.style.overflow = "hidden";
wwLib.getFrontDocument().documentElement.style.overflow = "hidden";
}
and this when closing the modal
if (context.browser?.["environment"] != "editor") {
wwLib.getFrontDocument().body.style.overflow = "auto";
wwLib.getFrontDocument().documentElement.style.overflow = "auto";
}
this will only apply in the published app, if you want to test it in editor remove the if part