I open a SP.UI.ModalDialog.showModalDialog 
function openPop()
{
    var notaID = $("#hiddenIDSpan").text();
var options = {
    title: "TITLE",
    width: 700,
    height: 700,
    url: '/Lists/NameOfList/NameOfPage.aspx?NotaID='+notaID};
SP.UI.ModalDialog.showModalDialog(options);

}

In that new ModalDialog i have a button that open another SP.UI.ModalDialog.showModalDialog and then, this is the ERROR. Does somebody know why?

1. Uncaught TypeError: Cannot call method 'parentElement' of null sp.ui.rte.debug.js?rev=%2BIbgsl83veG0lHyYqlfF4g%3D%3D:2694
   1. RTE.Canvas.checkCurrentFocussp.ui.rte.debug.js?rev=%2BIbgsl83veG0lHyYqlfF4g%3D%3D:2694

   
   

• Edited by IvanRamosMCPD Thursday, September 26, 2013 5:48 PM

Does anyone have new information on this issue? We're running into the same error message, when we try to open up our default displayForm with RichTextFields on it.

Please be aware, that we migrated that content from SP2010 to SP2013, but that shouldn't make any difference in my opinion.

http://sharepoint.stackexchange.com/questions/38370/a-is-null-error-in-vanilla-sp2010-install