NJ Disposition of Property option to exclude from state tax does not change tax due

[jman3]

One of several transactions on my 1099-B is for a US Treasuries redemption showing the dates acquired and redeemed, box 1d (proceeds), box 1e (cost, which is less than amount in 1d), and box 1f (accrued market interest, which equals 1d-1e). My understanding is that my state of NJ does not tax interest or gains on Treasuries.

So in the New Jersey portion, the section on "Disposition of Property" allows me to check the corresponding box in the Omit column to exclude that listed sale from New Jersey tax if it is nontaxable by the state. When I click this omit box, it does not change my NJ tax due (which should decrease?). Is there a reason why that happens? Thanks!