tinymce.full.js
function (items) {
        var self = this, parent = self.parent();

        if (parent) {
          parent.insert(items, parent.items().indexOf(self), true);
        }

        return self;
      }
function (items) {
        var self = this, parent = self.parent();

        if (parent) {
          parent.insert(items, parent.items().indexOf(self), true);
        }

        return self;
      }
function ( items ) { var self = this , parent = self . parent ( ) ; if ( parent ) { parent . insert ( items , parent . items ( ) . indexOf ( self ) , true ) ; } return self ; }
Adds items before the current control.

@method before
@param {Array/tinymce.ui.Collection} items Array of items to prepend before this control.
@return {tinymce.ui.Control} Current control instance.
Adds items before the current control .