Volume Envelope Point - Vertical Lock while Moving

Sometimes I need to move a Volume envelope point left or right, but don’t want the point to move vertically (I want the volume of the point to remain locked). Is this possible?

I can select a group of points by Alt - ‘draw a circle around them’, then move the group holding Shift, which locks them vertically, but I can’t figure out a way to lock a single point vertically during move.

Not possible. But this should and I will change it.

Thank you PG.