I have a tree table that allows the user to group columns arbitrarily. Is it bad UX for me to move the grouped by columns to the front of the table right next to the tree controls? Would it be more ideal to duplicate the columns and place them under a column group with the tree controls and leave the original columns in their positions?
So the scenario is a Tree table start state, the user then "groups by C," and I programmatically behind the scenes move the column up next to the tree controls, is this the Least Surprise?
If you would be surprised, what would you expect to happen?