Add the following snippet as a workaround -
Ext.override(Ext.Element, {
 findParent : function(simpleSelector, maxDepth, returnEl){
  var p = this.dom, b = document.body, depth = 0, dq = Ext.DomQuery, stopEl;
  maxDepth = maxDepth || 50;
  if(typeof maxDepth != "number"){
   stopEl = Ext.getDom(maxDepth);
   maxDepth = 10;
  }
  try {
   while(p && p.nodeType == 1 && depth < maxDepth && p != b && p != stopEl){
    if(dq.is(p, simpleSelector)){
     return returnEl ? Ext.get(p) : p;
    }
    depth++;
    p = p.parentNode;
   }
  } catch(e) {};
  return null;
 }
});

JavaScript