Improve List by Selection Contents group layers

[JimmyBowden]

When I have group layers in a map there are times when I want to toggle selectability for many layers. When I do a shift+ it only highlights the "group" not the sub layers so I can't quickly toggle them on/off as shown in the image. It should highlight the subgroups.  Currently I have to shift+ in each group.  With the Utility Network using subtype group layers there could be 6+ group layers that each group has to be toggled in sub groups.