When gnome-terminal shifts from showing a single tab to showing two or more tabs, it introduces unnecessary chrome on the left, bottom and right edges of the window. This is particularly visible when the terminal is maximised. Chrome on the right is masked to some extent by the scrollbar there, but should be eliminated as well.

To reproduce:
 * launch gnome-terminal, showing only a single tab, maximised
 * note the lack of chrome around the edges of the screen
 * ctrl-shift-t to create a new tab

What happens:
 * you see a gray border on the left and bottom of the screen

What should happen:
 * there should be no gray border on the left and bottom of the screen