As a SimpleViewer-Pro user, you could upgrade to the latest version (v2.3.1) to ensure that any bugs that existed in previous versions but have since been fixed are not contributing to your problem. Please see the SimpleViewer Version History for a full list of changes.
The 'Upgrading SimpleViewer-Pro' support page can be found here.
Also, you could try validating the HTML code on your web page with the W3C Markup Validation Service and fix any errors reported.
You can do likewise with the CSS code on your web page with the W3C CSS Validation Service.
Once the code on your web page validates correctly, your web page should be rendered with greater predictability and consistency across different browsers.
Depending on the layout of your page, you might like to try Using a Resizable Gallery with a Header whereby you could have a header (and/or footer) on your web page and have SimpleViewer resize to fill the remaining browser window without any scrolling at all.
SimpleViewer Support Team.