Did you point the mouse over the line until it indicated you can click-hold and 'drag' the line up/down?
Normal windows behavior is the mouse changes to a finger pointer .. as opposed to an arrow.

You don't just click, you drag it up/down.
FWIW my line appears yellow, but I may have caused that somehow. I like to tinker with stuff..


I do not work here, but the benefits are still awesome
Make your sound your own!