Why does turbotax page *not* accept the value I enter in the "enter u.s. government interest" field of the 1099-DIV form?

The turbotax page accepted all of the other information I entered into the form.  I checked the "a portion of these dividends is U.S. Government interest" box, no problem.  Then, on the next page, after I enter a dollar value to indicate the "amount of dividends reported on this 1099-DIV" and hit "continue" button, the amount I entered does not register.