nested scrollable element

[sanafathii]

I have offcanvas in my page that scrolled and in offcanvas I have a select option that scroll too but when in offcanvas use PerfectScrollbar select option doesn't scroll . how can I fix it .

it's my js code :
let slice = Array.prototype.slice.call(document.querySelectorAll("*")).filter(
e => e.scrollHeight > e.offsetHeight
);

let elements = slice.filter(e => {
var style = window.getComputedStyle(e);
return [style.overflow, style.overflowX, style.overflowY].some(
e => e === "auto" || e === "scroll"
);
});
if (elements.length) {
elements.forEach(e => { new PerfectScrollbar(e, { wheelPropagation: true }); });
}