arming instrument tracks & lock on control surface conflict

[circuitb]

hi all,
just have a quick test with ableton live 8.2.2 + apc40
and there's a strange bug/feature????
lets say we always want the first device/rack of the track to be the blue handed one (no matter the type midi/audio/instrument/rack...etc...) for remote purpose :
it doesn't work for instrument tracks eg : midi in / audio out

1/ create an instrument track with 2 devices : 1 midi effect/rack + 1 instrument
2/ make sure the blue hand and the lock on APC 40 is on and focused on the first device/rack
3/ disable the arm button
4/ select another track (mouse or apc)
5/ re select the instrument track (mouse or apc track selection)
6/ Arm the track

result is : your first device/rack that was previously blue handed is no more the active one
live seems to select by default the device who have a midi input and an audio output (instrument device)
is it a feature ????
thanks