I have a k-1 flowing through a partnership return with income (LTCG only) sourced to Massachussetts and I'm having difficulty allocating the LTCG given the apportionment is actually 0%.

Is there a way to directly allocate income to Massachussetts?  I've used the adjustment feature to back out other income line items that leaves me an amount being reported on Line 21 Differences and adjustments r