The reason behind this is because Yellowfin is not a web-page, you do access it via a browser, however this is a Java application.
You will not be able to use the 'back' button without running into issues, it could work ok in some cases (e.g. Go to 'My Profile' from dashboard, then hit 'back'), though it is still not supported.
If you would like to go back to the original result set after drilling down, you should use the drill down reports function that will provide a breadcrumbs link (please see Reset Report & Drilling Up section).