Finally I manage to get rid of the "ghost button presses" by adding the pull up resistor 10k to each column. Thanks for letting me know.
Now with firmware v20141119, I find out that the axis value on the "Joystick axes" page is different than "Joy-tester" page. So which one is the correct one?
min center max X 122 2059 3975 these values from Joy-tester > raw X 676 1984 3308 these values from Joystick axes > value
Y 161 2168 3866 these values from Joy-tester > raw Y 1724 2496 3180 these values from Joystick axes > value
I use hall sensor for both x and y. Are these values good enough? or do I need to better align the magnet - hall sensor?
Also I have enabled the auto calibration w/center for both axis, but when I look at control panel > game controller, I find the axis is not centered.
Then I calibrate it from setting > calibrate, but it seem the result is not optimal, the axis is still not centered.
Please let me know what is wrong and how to fix it.