ALL-LINKED feature on channel strip not working?

[lululu]

Hi all
I recently had a play with the channel strip dynamics module. I'm inserting it into a 5.0 dx stem (as a 5.0 multichannel instance, not multi-mono) for overall compression. What I would like is to have equal gain reduction on all channels as soon as one of them hits the threshhold.
According to common sense as well as the manual the ALL-LINKED setting should do just that, however when I insert a trim, unchain it and increase the level of just the center I can see that only the C gain reduction increases...
The only way to get what I need is by using a side chain and trigger it from C channel...
Could someone confirm this behaviour or kindly let me know what I'm doing wrong?

Thanks a lot!
M