timidi
if it's not a "bug", then it's just a stupid idea.
If I open the automation lanes to work on a pan envelope (that I created) and adjust the delay send (that I created) and maybe pull down the threshold a little in the chorus on the compressor envelope (that I created) why should I always have to look out for and remove a rogue volume envelope (that I didn't create). If I don't remove it, any adjustment I make to volume using the fader will not work.
If you start your automation by right-clicking the control you want to automate, and choose Write enable you won't run into this. Incidentally, and this sort of addresses the comment made by icontakt above, if you choose to use the "-" control to "Remove Automation Lane" on a virgin envelope, it will do just that, remove it completely. It's only when at least one additional node is added that the Lane is removed but the envelope reverts to it's ghosted state in the parent track.
Actually, probably the volume faders and sliders should override the volume envelope, not the other way around. So that once an envelope is created (or not), the faders and sliders work in a sort of offset mode moving the envelope (and nodes) globally.
I could not disagree more strongly. What would happen to all/any subsequent level changes the envelope is attempting to write? Does the fader revert to the envelope position once you finish touching it? Or does it stay where it is and offset every subsequent node. Not only would this be a bugger to program, I can see users getting into a right mess trying to work out what's going on.
Don't forget, you do have several options when using the faders to automate - Touch, Overwrite & Latch. And you have Offset Mode for affecting an entire envelope.