The cash div will be deposited to your RRSP account. Any withdrawal from the account will be taxed like any other withdrawal: the withholding tax rate (that the bank has to do by regulation) is 10% up to $5,000, 20% from $5,001 to $15,000, and 30% for withdrawals of $15,001 and up.

The withdrawal would be part of one's income and will be taxed like other income, and the rate would be based on one's total taxable income for the year.

That's why the NR says something like: "the cash dividend is usually tax-free"; but will be taxable if the stocks are in a RRSP account since the fund was tax deductible when it went in.