Watched/pinned repos appear on the tab strip at the top of the UI, similar to the MRU list of repos in TBPL. A common TBPL workflow for me, is to spawn another TBPL tab (opened directly at the desired repo) by middle mouse clicking the repo name in the MRU list at the top of the TBPL UI. In treeherder the equivalent of this is the watched repo tab strip - so it would be good if those had a link target set, to allow easy jumping to another repo in a new tab. I guess this partly depends on the outcome of bug 1032220.
We could add another button to the watched repo to "open in a new tab" button.
Could we just set a link target so middle click and the context menu work, but left click interacts with the UI as at present? Adding another button will take up more screen estate.
Let's fix this as part of bug 1125352.