Problem getting "12 mode" to work correctly

I built the squarebot using the instructions and I’m having trouble getting single stick control mode on the transmitter, or “12 mode,” to work. I first tried “23 mode,” and everything worked fine. Each control stick controlled one of the two motors.

However, when I tried to get “12 mode” to work, things didn’t go as expected. After I switched into “12 mode,” moving the right stick forward and backward caused only the right wheel to go forward and backward, not the expected both wheels. In addition, side to side movement of the right stick caused the robot’s right wheel to correctly move either forward or backward, but still not the left wheel. I was wondering what was going on, and I tried moving the left stick forward and backward, and the left wheel correspondingly moved forward and backward. It was like the left motor was in “23 mode,” and the right one was in “12 mode.”

What I’m doing wrong?

What you are seeing is what would be expected if you do not move the motor connected to port 3 “Left Motor” to port 1. The motors can not stay connected to the same motor ports for Drive Mode “12” and “23”. See Logic section “Port Mappings” of the Inventors Guide for more details.**