On Tue, Jan 28, 2014 at 08:32:39PM -0500, Paul Davis wrote:

> loading a snapshot and then saving will alter the state of the
> snapshot that was loaded, not the "current session" or any other
> snapshot.

That exactly is the problem. I would expect things to work as you
decribe when a 'save as' file is reloaded, and that is also what
happens of course. But I wouldn't expect a snapshot to be modified
by a normal 'save' but only when the user explicitly asks for it,
by using 'new snapshot' with the same name (which would have to be
typed in manually). Overwriting snapshots to me feels like rewriting
history, or bypassing a version control system.

The root of the problem is that files created by 'new snapshot' and
'save as' are identical, and both are treated as 'session files' when
reloaded. But the user's intention behind creating either of them
is likely to be different. That intention is handled correctly when
the files are created (a snapshot won't be modified by later changes),
but not when they are reloaded.