I just lost a lot of typing because there was an unspecified error with "adding some reviewers". And the Error mesage doesn't even give me any details. Message text and reviewers list is lost.

There is a simple Fetch button available in the toolbar, so we don't need the fetch from the popup.

Just make the Fetch button a default, so everyone sees it, even those who don't think about changing the toolbar.

I'd like the same functionality for all triangles. Pull Requests are hidden as soon as you finished the last one, and when new requests come in, you have to open them again - easy to overlook.

I'd love to see the branches when I'm filtering - this would work nicely with the proposed highlighting.

Tooltips could be larger than one line...