I am a non resident of Georgia, but why does my interest income, dividend income and capital gains income shows up as Georgia taxable income?

[MaryK4]

As a nonresident, you only pay tax on Georgia source income, which includes earnings from work performed in Georgia, and income from real property located in the state.   You will calculate a base tax as if you were a full-year resident, then determine the percentage of your income that is subject to Georgia state tax and the amount of tax apportioned to Georgia.