The Kendo UI Editor widget comes with a tool formatting tool that can be activated using the tools option. It renders a dropDown with different entries representing the supported formatting styles. As you can see in this DOJO, the entries are overly large. This comes from a syntax error in the inline style applied to the span inside the .k-list-item-text DOM element (display: inline-block#; instead of display: inline-block;) This causes the browser to ignore this line and leads to broken styling. Fixing the syntax error in the browser console fixes the styling issue.