No option to check for adding cetain layers in the layer group

I want to add certain layers into a layer group, there is no option to give multiple check to cartain layers…has to add each layer. if we add a layer two times int wil go through…there should be a check if the layer exist already in the group. no option for select all. there should multiple option in the panel. screenshot attached

Adding the same layer twice is a valid option often with different stylings. Also if we allowed multiple selections at the same time then it would become difficult to control the order that the layers are in.

Ian