This is odd. I i would change say, a resistor to another footprint, then I have first add that footprint to multisim ? The earlyer versions dont behave like this. Sometime i feel the newer versions not always better. For example, now if i have a smd component on the top side of the board, i could wire it with the bottom copper was selected. The wire is snap to the smd pad, like the smd was on the bottom side...