meld future ui

[Stephen Kennedy <stevek gnome org>]

While I think having notebook tabs in melds interface is
indispensable, there's one thing
which isn't wholly successful and it's the fact that filediff, dirdirr
and vcview tabs are "equal".
But really for me they're not equal - I usually have one vcview or
dirdiff "core" tab which
spawns several filediff tabs.

The core tab is in some way special - I'll often switch back to it,
close all spawned tabs
and it's pretty annoying to close it accidentally.

So the question is, how should that be reflected in the interface? For
instance what about
one unclosable core tab per top level window? (We'd also support a
"null" core tab so you
can open several file comparisons in a window) Any other suggestions?
Even if it's just
"maintain the current interface". Hopefully nobody wants nested notebooks!

Stephen.