Short Introduction on External Link:
The External Link is a functionality that allows to embed an external link into the custom ui.
The External Link has to be linked with an menu item in order to be available in the custom ui.
To create an external link open up the Edit menu, select New and click on External Link.
Click on the newly created External Link in Widgets to edit Name, Description and URL.
Remember to save all your changes in the File menu with Save.
