Code review comment for lp:~abudden/bzr/switch_parent_513709

The background for this (in addition to the bug report) is I'd really like to see the "changes relative to parent" view when using bound branches with a feature branch model. I think this is the first change that is required, but in Bazaar Explorer's view_workingtree.py there is the comment:

        # Display the delta versus the submit branch iff one is
        # defined and it's local. Unfortunately though, merging a feature
        # branch into trunk sets the merged-from branch as the submit
        # branch which means we see a "silly" submit delta panel for trunk.
        # To work around that, we don't show the panel for bound branches
        # as trunk ought to be bound. We could look for the name
        # "trunk" instead but that sounds even more of a hack. :-(

I'd also like to explore the background to this as this means even with this merge proposal, I can only view the changes if I open the master branch and not if I open the bound branch.