I often use stacks of grouped elements to detail/organize widgets by feature classes. I would be helpful to have the ability to apply actions to stack elements to bring that element to the foreground of a stack when a feature class is selected in another widget (map, list, etc). An example of how I'm using a stacked group can be found in this post.
Have a stack of elements. the stack becomes the target for an action. each element in the stack would be selectable as the "focused" element within the sub menu for that action.