Comment 15 for bug 769644

OK, I found the origin of the problem:

In the lxpanel config file

   ~/.config/lxpanel/panels/panel,

there is a plugin "volumealsa" which causes the misbehaviour. I just commented out the three lines

# Plugin {
# type = volumealsa
# }

and after restarting the lxpanel (logout/login), Alt-F2 works. However, the execution window appears unfocused, but this is dealt in bug #889414 (with workaround).

This is a workaround I can live with, but still:
By commenting out volumealsa, I do not have a volume indicator any more. Anyone knows, why the plugin volumealsa makes problems? Is it just, that I would need to install some additional package?