I'm sure that I'm just missing something in the menu settings, but sometimes my VX8R will change volume settings apparently by itself between one day and the next. I use it at work to scan local EMS and Law Enforcment channels. While scanning the various banks which I have set up, it sometimes requires me to push the FW key in order to change volume, but other times the main dial and up/down buttons are always stuck on volume adjustment, and in order to adjust scanning, frequency, etc, I have to press the FW key. What am I missing?