Standard Window: allow pushing to multiple remotes

Wow, the new standard window looks really great! There's a lot to love here. Nice work!

However, there's one missing feature that currently breaks my workflow: pushing to multiple remotes.

Even though all the remotes display correctly in the UI (like in the history log view), the push button only seems to push to one of the remotes. And I can't find a way to choose which one it is. I found a "Push up to" option in the "Remotes" menu bar, but it's always greyed out. I don't know what conditions are necessary to activate it, and I couldn't figure it out after fiddling with the UI for several minutes. As a result, I can't push to all of my remotes. Just one of them, chosen seemingly arbitrarily.

Ideally, what I'd like is some way to choose which remote to use when pushing, each time I push commits. Some kind of popup to confirm the push and the choice of remote for that push would be nice. The popup UI could even fill out a reasonable default remote for each push, but I'd like the option to explicitly configure that default value as well.

The old (non-standard?) window allows a similar workflow in the "Push to" command, so that's a good fallback for now.

Another way to do it would be to have some place in the UI that lists all the remotes. Then pushing to that remote could be activated from a context menu. That context menu could do other remote-related actions too, like editing. The old (non-standard?) window has something like this in the "Branches" view.

Thanks!