In a Grid, you can include aggregates from other columns in a footer template. Please add this feature to TreeList.
Also, other useful features would be:
1. Enable or hide footers for expanded nodes. Currently, if there are any footer templates defined, then a footer row is rendered for each expanded node. Please can we have some control over which of these footer rows are rendered. For example, having them rendered only at the top level.
2. Provide some means of controlling whether or not to include child rows' values in the aggregates.
For example, I currently have a TreeList where some values are already the totalled across any child rows - this totalisation is done by our business layer. However, we want to include a Grand total in the footer, This Grand Total needs to be the total values summed on the top-level rows ONLY and not their children. I am having to write custom code to do this.