If I run Audacious via keyboard shortcut, there will be no indicator-sound playback menu for that app on my top panel, below the speaker icon. However, if I double-click the audio file (or if I click at "Audacious" right below the speaker icon from the top panel), the audio controls (previous, play, pause, next) will be visible there, as expected.
Here's the screenshot what's happening when I run Audacious via keyboard shortcut. There is no playback menu within the indicator-sound for Audacious.
I guess it could be a bug. Is there a fix/workaround for this?