We implemented custom
Content Editor Web Part, inside that we are using the
sp.ui.rte.js file. It is working fine up to IE10. Our project users upgraded from IE10 to IE11. When we edit the content editor web part we are getting below error:
SCRIPT5007: Unable to get property 'classname' of undefined or null reference File: sp.ui.rte.js, Line: 2, Column:35101
Please let us know what is cause of this issue.