demo/amd/rjs/output/unified/marionette-build.js
function() {
      this._ensureViewIsIntact();
  
      if (this._firstRender) {
        // if this is the first render, don't do anything to
        // reset the regions
        this._firstRender = false;
      } else {
        // If this is not the first render call, then we need to
        // re-initialize the `el` for each region
        this._reInitializeRegions();
      }
  
      return Marionette.ItemView.prototype.render.apply(this, arguments);
    }
function() {
      this._ensureViewIsIntact();
  
      if (this._firstRender) {
        // if this is the first render, don't do anything to
        // reset the regions
        this._firstRender = false;
      } else {
        // If this is not the first render call, then we need to
        // re-initialize the `el` for each region
        this._reInitializeRegions();
      }
  
      return Marionette.ItemView.prototype.render.apply(this, arguments);
    }
LayoutView's render will use the existing region objects the first time it is called. Subsequent calls will destroy the views that the regions are showing and then reset the `el` for the regions to the newly rendered DOM elements.