Since Vaadin 7, the UI (root element) has the Navigator API built-in, which is aware of the page URI and fragment, but we don't use it at all for location handling.

What happens currently is the following:
1. Select a row in the tree
2. Sends a UIDL request to server
3. Updates magnolia location fragment
4. Client-side repaints
5. Vaadin's VUI sees a location change on the client-side, which differs from its server-side state.
6. Makes another UIDL request to say client location changed
7. Updates UI page fragment
8. Client-side repaints again

There is an easy fix consisting in updating Vaadin UI' page fragment at the same time we set the magnolia fragment. Then when VUI will listen to location changes, it will no longer be out of sync with its state.