By overriding _getChildByEvent method of dojo/dnd/Container we can enable dnd of any row also on another level of the tree not just first level

extend_container.js

require(["dojo/_base/lang", 'dojo/dnd/Container', 'dojo/dom-class'], function(lang, Container, domClass) {
  lang.extend(Container, {
    
    _getChildByEvent: function(e) {
      var node = e.target;
      if(node){
        /*
        for(var parent = node.parentNode; parent; node = parent, parent = node.parentNode){
          if((parent == this.parent || this.allowNested) && domClass.contains(node, "dojoDndItem")){ return node; }
        }
        */
        
        var node_found;
        for(var parent = node.parentNode; parent; node = parent, parent = node.parentNode){
          if(domClass.contains(node, "dojoDndItem")) {
            node_found = node;
          }
          if((parent == this.parent || this.allowNested) && (typeof(node_found)!='undefined')) {
            return node_found;
          }
        }
      }
      return null;
    }
  });
});