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

Description

When triggering a popup, typically via a  Click Open trigger, your website or page will "jump" to the top a split second before the popup is displayed.

Cause

In most situations, this is caused by using the CSS example (5a) in Solution #5 (see:   Why Is My Popup Not Scrolling Properly/Background Scrolling ).

Solution

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