If you extend the width of a gnome-terminal, then drag the menu bar to another location (the bottom for example), the width will reset to the default width.
I'd predict that this is caused by Zvt's questionable size_allocate behavior, so may be a gnome-libs bug
Will defer this to the GNOME 2 upgrade. GNOME 1 is only getting showstopper/release-critical fixes at this point.