I was having problems with my sound -- outgoing (the microphone). It kept turning the sound down. After advice from webex that did not work, i went back through the audio set up and at the end, turned of the auto gain choice. Now the slider stays where I put it. I can't imagine why webex did not realize it was the default setting that needed to be changed. For my old web cam, the defaults worked just fine, but did not with the new - better web cam. So if your slider for sound does not stay in one place, uncheck the auto gain control.
This may be a duh! -- but it took me a while to fix it. And it had also worked before their last update -- so it was not a duh for me.
Judie Eatough