MD5: Hide backlight adjust item from preferences if backlight is controlled by program.

I'm using a math channel to add a value stored in an adjustable integer parameter to the measured brightness value to control the backlight. I would like the ability to hide the backlight adjustment in the display preferences menu as this will cause confusion since customers familiar with the MD4 will go there to adjust the backlight, instead of the adjust group.

Or you could just add an ambient lighting adjust mode to the preferences screen so the operator can easilly chose how they want the backlight to operate. That'd probably be a better option.