If this helps with recalling the fix, the following is the error reported by the javascript console in Chrome, also shown with attached screenshot:
standard_text_editor.js:29 Uncaught TypeError: Cannot read property 'style' of nulland the referenced code snippet:
24 function showHTML(id,html) {
25 if (menus == null) return false;
26
27 for (var i in menus) {
28 if (menus[i] != html) {
29 get_object(menus[i]).style.display = 'none';
30 }
31 }