In order to use TheDock (that is exporting any changes made in to your theme), you need a valid license.
A single domain license can be activated on one domain at a time. This means you can change your domain without purchasing a new license, but you can not use the same license on multiple domains*
* We make an exception for the following subdomains, allowing you to use the same license for production and staging: stage.mydomain.com, ww2.mydomain.com, test.mydomain.com