Complex power delivered by voltage source (with current source)
Generally power cannot be found out separately by using superposition principle, since power is parabolic with reference to current.

When you find the power delivered to an element of impedance Z through which current I flows, the answer is (I^2)*Z;

When you use superposition, then you get current due to both sources individually as I=I1+I2;
When you calculate the power individually, due to the individual sources, you would be getting P1=((I1)^2)*Z and P2=((I2)^2)*Z; hence you would calculate the total power to be P=P1+P2=(((I1)^2)+((I2)^2))*Z; which is incorrect since the total power is P=(I^2)Z=(((I1)^2)+((I2)^2)+2(I1)*(I2))*Z;