Thanks, Justin,
In the link, he says:
You can add some simple styles to your site's style sheet to force a vertical scrollbar to always show and thus get rid of the page shift. The most obvious solution is to add an overflow: scroll rule to the html element. However, this rule adds a horizontal scrollbar as well, which web users definitely don't like. Here's an easy and valid way to force only the vertical scrollbar to appear, no matter what size the viewport is:
html { min-height: 100%; margin-bottom: 1px; }
If I am using the mystyles.css to modify the default SiteAssist Pro CSS, where do I put this HTML code? Do I have to put it on all pages????