keep tracks of sound level depending on output, distinguish both sound level for speaker of jack/accessories

[hd66]

it's both hw and sw related

on LMDE5, when using the jack accessorie, eg handset, headphones.. the sound is at 50%.
when i remove it, i ask a first time to get the sound muted.
when i plug back the headphone on jack, it automatically restores the sound at 50%.

means the sound keeps track and save the status of each sound level regarding if it's speaker (eg mute) or headphones (eg 50%)

well, on LDME6, that nice behaviour looks disappeared.
it's very very pratical to keep distinguished the both separate levels of each output (jack or speakers) instead of a common one.

here on LMDE6, when i unplug the jack headphone, the speaker is not muted but gets the same sound level as the jack one, instead as the one that speaker had (eg mute)

why isnt it working as LMDE5?