Oh now I got it - sorry about that. I'm still new to MacHg and in the terminal I've only provided the destination name.
Just "Push <source>" would be fine I think.
Maybe it would be a more intuitive way to only provide a modal dialog if there is a actual possibility to choose between multiple repositories. This really depends on how people are using mercurial. Whether they use a lot of destination repositories or not. For me it would be nice to never show a dialog if there is only one repository and to show a simple selection like in the example UI I've attached if there are more.
Very interesting idea!! Thanks for that. I regrettably probably won't go with it since it will break the normal model of working here and also since it would be a good bit of work which I could put into other things... But it definitely is a very interesting idea. If you have other ideas about other parts of MacHg please send them along... Especially with mockups like you sent. Very very helpful! They are very nice to get ideas from...
As such I'll resolve this report if you have no objections, but again thanks!