After switching audio output to a bluetooth speaker the Volume Control widget in the panel cannot be used. A manual setting is needed to select the new output in the widgets' configuration.
I could add a second instance of Volume control widget to the panel and try to use that only for bluetooth, but that looks a bit odd...
Is there some way to make the LXQt panel Volume Control follow the actual audio output?
Can I use a different volume control tool with that panel?
A solution is to use a different tool and remove completely that widget.
By default the actions on the tray icon don't affect the bluetooth speaker, until that speaker is selected as master channel (righ-click the icon, "Select Master Channel").
It shows no volume change pop-up on mouse actions on the tray icon (at least not in this LXQt).
Resize the window and drag it close to the volume icon.
It doesn't show a slider, nor a pop-up, and mouse actions are limited to scrolling volume up-sown (no mute), but it has other useful options like switching the audio output. More here.
Add
qasmixer -t
(start minimized in tray) and/orkmix
&pasystray
to startup list.Furthermore, if the bluetooth audio device volume cannot be controlled through the laptop keys, the following commands could be associated to the keys:
Sources: Terminal command to set audio volume? and How do you mute from the command line?.