Simple and functional addon. The toggle button appears in the URL bar and is only visible on the Ancestry.com website. The resulting style is a clean white background with only the family tree itself and Zoom, etc. controls visible. The style allows the family tree to be moved via the scrollbars, rather than the Ancestry.com default drag-to-move-the-view controls. Very convenient when trying to take full-page screenshots of the entire visible family tree, which was my reason for installing.