The footer CSS has position: absolute and had a variable height. Since the footer can contain error messages from plugins, the height would grow to cover up actual content (console logs, etc.).
For example, the scm-sync-configuration plugin has the option to put scm failures in the footer. It adds as many newlines are there are failing commits, which can be many lines until someone fixes the problem or clears the log. The footer expands upwards and occludes the console log, which makes diagnosing failed builds problematic.
See the attached screenshot. When