The porpouse of the Grouping Feature is to better organize the number of objects. Actually it is possible to edit a group by: - dividing a group - ctrl + select tool to select an element without changing the group itself - bouble click on the group to enter the group and double click outside the group to exit
Expecially the third point needs to be improved by a visual point of view.
Groups of ombjects has been given a better visual definition while working on them.
[ enter more specs at the end of the drafting ]
There are two main goals:
1) highlight the type "group"
2) highlight when editing a group
What is this?
When selecting something I think it could be useful to know that actually you're selecting a group or not.
Here's what I'm thinking about 
Am I editing a group??
Once the users decide to edit a group, he has different choices. One could be to remove the group, move the object and set the group again. Another one is to select an object, that you know is inside a group, with ctrl+click and move it: in this case the group is changed automatically. One other way, is to doubleclick on the group, enter it, make changes, and doubleclik outside the group to exit it.
In the last two cases, I think that it would be better to actually indicate that the user is editing a group, with a simple square around the objects that remains there to warn the user, until he exits the group.
So, here are some snapshots:
1) when the user enters the group, the objects ot the group should be highlighted in some way 
3) same thing should be applied to the groups inside groups 
 highlight the groups on selection
 highlight the elements of a group while editing inside the group