MAGETWO-90591: Add Selected Button shouldn't be enabled if there are no images available

Author: Joan He

app/code/Magento/Cms/Block/Adminhtml/Wysiwyg/Images/Content.php

@@ -78,7 +78,7 @@ protected function _construct()
 
         $this->buttonList->add(
             'insert_files',
-            ['class' => 'save no-display primary', 'label' => __('Add Selected'), 'type' => 'button'],
+            ['class' => 'save no-display action-primary', 'label' => __('Add Selected'), 'type' => 'button'],
             0,
             0,
             'header'