Help with scrollbars

I have a frameset with two frames. For both frames, I set scrollbar=auto (which is by default). So when there is a lot of content, scrollbars appear, and when it fits on one page, there is no scrollbars.

However, I notice that when the scrollbars are not visible, there is still some whitespace reserved for it all the way down the right side of the screen.

I notice this because in the body of the page, I have a DIV element and I set its background color to black. And the black does not reach all the way to the right edge of the screen.

How can I eliminate the white space?

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