fix: isolate document surface and toolbar/ruler stacking contexts#2491

harbournick merged 1 commit intomainsuperdoc-dev/superdoc:mainfrom

nick/sd-2015-bug-structured-content-flows-over-toolbar-while-scrolling-insuperdoc-dev/superdoc:nick/sd-2015-bug-structured-content-flows-over-toolbar-while-scrolling-inCopy head branch name to clipboard