The Calif nonresident/part-year return, Form 540NR, computes your income and tax as if you were a resident the entire year, then computes a net tax rate by dividing the total tax by total taxable income. Your California-source taxable income is then multiplied by that net tax rate to determine your California tax. You can see this on Form 540NR lines 31-37.
So you do report everything but towards the end of the interview (Nonresident Adjustments) is where you allocate the California-source income which is multiplied by the net tax rate. See Form 540NR, lines 31 - 42 and Schedule CA(540NR).
On the screen titled Your California Tax Summary, your actual Calif taxable income is on the line, "Income After Nonresident Adjustment".
