Well, that widget may not transferred as you would think. It may simply redrawn in the new position. To make an object looks like it is moving, you need to make a loop that looks like something like this:
movement_speed = 10; old_y_position = 0;
new_y_position = 200;
for( ; old_y_position <= new_y_position ; old_y_position++ ) {
Sleep(movement_speed);
mtitlebar->SetPositionY(old_y_position);
}