I have a new laptop. Because I switched from a desktop computer my usage is a little different. Also, because this laptop is much more powerful than my old computer I switched from Xfce4 to Cinnamon. I don't know if that latter fact is relevant.
So I installed Debian Jessie, with the Cinnamon desktop, and my home partition was completely empty so that the configuration is now mostly the defaults. There is something with my system which I am finding extremely irritating. That is, my sound settings keep changing.
Say I bring my laptop into my office, plug my screen, keyboard and speakers in, because I want to go to put some music on. Fine, I'll fire up rhythmbox and find the playlist I want, and press play. Then I find that the sound has been muted. I did not mute it myself, but I think something muted it when I plugged the speakers in.
Then I'll load a page in firefox. That page has an advertisement or a video that emits sound, so that suddenly mutes the headphone jack and puts the internal speakers on. Why is this happening?