The Save button is very important and should always be remembered to use before closing, or when you want to preview the changes that you made. A change made in the template editor it is not immediately implemented and is temporary. When you save your changes, they will be implemented and updated in the preview. So when using the modeler with the preview screen open, you should save after an edit. This will refresh your preview and update to the new changes. On some changes the refresh is not properly triggered and you may need a hard refresh on the preview page by refreshing your browser window.