Unable to disable 'Disable individual audio channel'

I'd like it to display only one single waveform instead of 2 wave forms. Resolve is refusing to revert back to it. The version I'm using is 15.

As seen in the image, no check mark displays.

Edit: I may have solved it. I clicked to a different timeline, then went back to the timeline I was working on, and only one audio waveform shows.

Right click on the audio clip and make sure Display Individual Audio Channels is not selected.