Capital gains for non resident partial year

[Bifftex]

Helping son with taxes. He worked 5 months in New Mexico. Lived the rest of the time in a Texas (no state income tax). I listed him as non resident on the New Mexico State income tax form. But what do I list for interest, dividends, capital gains/losses? The entire year’s worth or just the 5 months he was in New Mexico? I have yet to see a question asking what time he spent there (less than 6 months).

[MinhT1]

In general, interest, dividends and capital gains/losses are allocated wholly to the resident state. None is allocated to the non-resident state.

[wlin133]

How do you NOT allocate capital gains to the non-resident state?

I used to live in MA but now live in TX (for the entirety of 2019).  I'm filing MA state tax as a NON-RESIDENT b/c I still have some rental properties there.  For some reason, TurboTax is allocating my capital gains income to MA and showing MA tax due on it.  How do I exclude my capital gains from MA state tax???  

[ThomasM125]

As you go through the state return for Massachusetts (MA), you should be asked for each item of income, the portion that is to be allocated to MA:

You'll see an option to indicate that your capital gains were "Non-Massachusetts source":

[-Reese-]

When I entered each stock sale separately and check marked non-Massachusetts, turbotax doubled my capital gain amount.  Where am I going wrong?  I must be entering something wrong.  It seems as though the federal tax return capital gain transfers to the MA non-resident return and is being taxed as capital gains, even though the same capital gain I entered in the state return is not being taxed.

[-Reese-]

My federal entries are not showing up in the “easy steps”, so I cannot checkmark "non- Massachusetts source” without re-entering each capital gain into the MA non-resident tax return. Help!