Comment 1 for bug 538493

This is actually in libido, not in indicator-sound. It's also probably not going to be an obvious one to fix. The problem is that we do some rather janky things in libido to work around the gtk grab system. The slider widget adds a grab when you mouse-down on the slider, but this also forces the menu to close which is why we work around it.

We can look into adding more janky solutions, like trying to see if it's possible to stop the button release event on other menuitems in the menu.

Another solution might be to create a GtkMenu derivative which doesn't close when a grab is added. I don't know off the top of my head what other side-effects we may have from this though. It could turn out to be more gross going that direction.