Extend Inline editing

LongText field uses KendoUI Editor. You can customize the editor's tools by performing the following:

1. In your project, create a JavaScript file and call it LongText.js
2. Inside the new file, paste the following: 
   In the code above, you also customize the configuration tools. For more information, see Kendo UI Configuration tools.
3. From your custom file, add a new VirtualPath that helps Sitefinity CMS resolve the requested LongText.js. To do this, in your ~App_Data/Sitefinity/Configuration/VirtualPathSettingsConfig.config file, as a last line inside the <virtualPaths>...</virtualPaths> section, add the following:
   <add resourceLocation="~/<file_path>/LongText.js" resolverName="Embedded" resolverType="Telerik.Sitefinity.Abstractions.VirtualPath.FileSystemResolver, Telerik.Sitefinity" virtualPath="~/Res/Telerik.Sitefinity.Web.UI.PublicControls.InlineEditing.EditableControls.Scripts.LongText.js" />
   Replace the ~/<file_path>/LongText.js, highlighted above, with the relative path to your custom LongText.js file you created in Step 1.
4. Save all modified files and restart the application.
   Inline editing starts using your custom JavaScript file.