When you go in the arrange window with mouse over the S buttons there is a hint
ALT + Click (Solo Defeat) (in C6.5 it works fine with only ALT + CLICK)
This is not working (only in the Mixer)
In the Arrange Window (Tracks) you need CONTROL + ALT + CLICK for Solo Defeat !!
I think they need to do something - either restore the Alt-click behaviour or change the help text. And the manual.
I hope that this: Steinberg Forums in the Solved Issues sub-forum doesn’t mean there will be no return to the old behaviour. I’m with whoever said it earlier - why change? I would guess there’s been a c-u but it’s not critical so will be let be.