Weird stick configuration

Hello. I am completely new to the RC plane and I just started to use Mission Planner (MP) today for the first time, so please forgive me if I am asking very basic things.

I use Pixhawk (HKPilot32 purchased from HobbyKing.com) with Spektrum AR7700 receiver and Spektrum DX6i transmitter. I just finished the initial setup, and all green bars in Radio Calibration setting move when I move the sticks on the transmitter, but when I move the throttle, roll on the MP moves, when I move the pitch, throttle on MP moves, and when I move the aileron, pitch on the MP moves. So only the yaw stick is assigned correctly. I checked that my transmitter is in Mode 2 (throttle and rudder controlled with the left stick, and pitch and aileron controlled with the right stick), and I also checked that the RCMAP_PITCH is 2, RCMAP_ROLL is 1, RCMAP_THROTTLE is 3 and RCMAP_YAW is 4 on MP under the Full Parameter Tree, which I think is same as the transmitter’s setting. So why the throttle, pitch and roll settings on MP are different from the setting on the transmitter? And how should I make changes on MP?

I would appreciate any help from you.
Thanks.