1) fill out the entire Federal part first...everything..do not start the state parts until Fed is fully filled out. The state parts will assume a lot of income items are taxable in their state....but only until you actually work thru the state tax forms.
2) Then do the PA non-resident tax return..in there you will mark the PA W-2 as PA taxable income, and everything else as not PA taxable. The extra $ are not removed from PA taxation until you actually run thru the PA interview.
3) Finally, go thru the DEL interview. DEL assesses a tax on "Everything", even the PA income...BUT as you go thru the interview, look for a question about taking a credit for taxes paid to another state....that section allows you to take a credit for the taxes that PA kept (which is why the PA non-resident tax return has to be done before DEL)
4) You get the credit for the PA taxes paid in your DEL return.
