MAGETWO-54816: Styles drop down in WYSIWYG editor does not work

lib/web/mage/adminhtml/wysiwyg/tiny_mce/setup.js

@@ -136,6 +136,10 @@ define([
                 }
             };
 
+            if (!settings.style_formats) {
+                settings.theme_advanced_buttons1 = settings.theme_advanced_buttons1.replace(',styleselect', '');
+            }
+
             // Set the document base URL
             if (this.config.document_base_url) {
                 settings.document_base_url = this.config.document_base_url;