WebGUI's Default Calendar Event Edit template (root/import/calendar-templates/default-calendar-event-edit) has one error in the template itself and one error in the CSS. The errors were discovered in 7.7.29, and have been confirmed in 7.7.32 via the webgui.org demo website.
I have attached edited versions of the template components to this bug report. For #1, look for the comment "Extra tags removed here" and for #2, look for the comment "The following declaration has been fixed".