demo/amd/rjs/output/unified/marionette-build.js
function() {
      if (this.isDestroyed) { return this; }
      // #2134: remove parent element before destroying the child views, so
      // removing the child views doesn't retrigger repaints
      if (this.getOption('destroyImmediate') === true) {
        this.$el.remove();
      }
      this.regionManager.destroy();
      return Marionette.ItemView.prototype.destroy.apply(this, arguments);
    }
function() {
      if (this.isDestroyed) { return this; }
      // #2134: remove parent element before destroying the child views, so
      // removing the child views doesn't retrigger repaints
      if (this.getOption('destroyImmediate') === true) {
        this.$el.remove();
      }
      this.regionManager.destroy();
      return Marionette.ItemView.prototype.destroy.apply(this, arguments);
    }
Handle destroying regions, and then destroy the view itself.