Why Does My Site "Jump" to the Top of the Page When I Trigger a Popup?

Description

A Click Open trigger can cause your website or page to jump to the top a split second before the popup is displayed.

Cause

This might happen if you implemented the custom CSS for smooth scrolling (Option 1). 

Solution

To fix this issue, use the following CSS (Option 2) instead. The styles are slightly modified compared to Option 1 CSS example provided in Solution #5.

html.pum-open.pum-open-overlay.pum-open-fixed .pum-overlay {
    overflow: hidden;
    position: fixed;
    width: 100%;
}
html.pum-open.pum-open-overlay.pum-open-scrollable .pum-overlay.pum-active {
    overflow-y: scroll;
    -webkit-overflow-scrolling: touch;
}

You can view the original CSS source on GitHub.