Actual Preloader

I updated the strip upon the home page and added the loading image added the following script. If the header not in fixed position it is working fine.
$w.onReady(() => {
export function button6_onClick(event) {
function waitForLoading() {
setTimeout(() => {
}, 1500);
If the header is freezed, than it is visibile above the loading strip. You can see through this link below. I need the sandbox header should be back to the loading strip while loading. Please look at this issue asap and let me know if you need any more information about this issue.