protected function initPanels()
    {
        // merge custom panels and core panels so that they are ordered mainly by custom panels
        if (empty($this->panels)) {
            $this->panels = $this->corePanels();
        } else {
            $corePanels = $this->corePanels();
            foreach ($corePanels as $id => $config) {
                if (isset($this->panels[$id])) {
                    unset($corePanels[$id]);
                }
            }
            $this->panels = array_filter(array_merge($corePanels, $this->panels));
        }

        foreach ($this->panels as $id => $config) {
            if (is_string($config)) {
                $config = ['class' => $config];
            }
            $config['id'] = $id;
            $this->panels[$id] = Yii::createObject($config);
            if (!$this->panels[$id] instanceof CmsToolbarPanel
                //&& !$this->panels[$id]->isEnabled()
            ) {
                unset($this->panels[$id]);
            }
        }
    }