Allow MASS SELECTION (lassoing) of keyframes on a SUBMIX tracks

Hi! I would like to suggest adding the possibilty of mass-selecting keyframes on the submix track.

I try to use volume automation on the submix track to set music volumes. It could potentially be an excellent way to simplify volume automation on heavily edited tracks. However the Submix track has a major flaw that makes it unusable.

The MAJOR hurdle is that there is no option to mass-select keyframes.

Currently, the only way I have found to select more than one keyframe is painstalkingly shift-clicking EACH and every one of them. I may have dozens! And I need to repeat this process every time I make any tiny change in the sequence! This kills any productivity gain.

(Another effect of this lack of mass selection is that there is no way to remove ALL keyframes from a submix track. You also need to remove each keyframe individually.)

Allowing mass keyframe selection options, like lassoing, would make Submixes so much more viable. However powerful they are, they're currently way too work-intensive to be used in most contexts.

Thanks!