If you are a Canadian citizen with a US greencard and both a US and Canadian residence, electing to pay Canadian income tax under the Canada-US income tax treaty may jeopardize your greencard status.
"This article provides information of a general nature only. It is only current at the posting date. It is not updated and it may no longer be current. It does not provide legal advice nor can it or should it be relied upon. All tax situations are specific to their facts and will differ from the situations in the articles. If you have specific legal questions you should consult a lawyer."