Hi ed - you mean you don't want the little indentation on the left and right sides?

That indentation comes from padding set on the moi:PaletteHeader elements that are the containers of those tabs.

You can remove that by going to moi.css, go to the rule for:

moi\:PaletteHeader {
<....>
}


Inside of that there is an property set for:
padding:0 0.35em;

That's setting the bit of left/right padding on the header so that any child content inside of it (the tab controls) is effectively indented on the sides.

Change that to say:
padding:0;

and then there will not be any indent.

- Michael