Fix a type in the Dict properties.

static/plugin_dbui/src/form/field/Dict.js

@@ -42,9 +42,9 @@ Ext.define('App.form.field.Dict', {
 
     /**
      * @cfg {Boolean}
-     * The columns header is hidden when true.
+     * The columns header are hidden when true.
      */
-    hideHeader: false,
+    hideHeaders: false,
 
     /**
      * @cfg {Boolean}