From the BBA:
The state taxation of fiduciary income depends on the state residency of decedents, grantors, trustees and beneficiaries. In Massachusetts, for example, the presence or absence of a Massachusetts resident trustee can determine whether or not an inter-vivos trust is subject to Massachusetts income taxation. The recent Bank of America case (decided July 11, 2016) describes when a corporate trustee is considered a resident of Massachusetts for Massachusetts fiduciary income tax purposes.
This timely program surveys the authority of the six New England states to tax trust capital gains.