Since recently in trunk, perhaps the last few weeks, I find that I
cannot revert to a previous version of a method from a VersionBrowser.

The problem seems to be that #listSelections in the VersionBrowser is
not being updated when I highlight one of the method versions in the
browser window. Presumably some update mechanism has been disconnected
between the PluggableListMorphPlus selections and the VersionBrowser
model, but I cannot spot the problem.

Can anyone think of a recent change that would cause this?

Steps to reproduce:

- In a SystemBrowser, select any method 
- Click the "versions" button to open a VersionsBrowser
- The VersionsBrowser will display "Recent versions of <foo>"
- Click one of the versions in the list to highlight it
- Click the "revert" button

Result: A UserDialogBoxMorph that says "nothing selected, so nothing done".

Thanks,
Dave