In the last couple of builds we have essentially rewritten the code that implements grouped queries. In the previous build we have added support for "server grouping", where grouping is performed on the server, rather than on the client as before. Since the client could only calculate group summaries within the currently displayed page, those summaries were often wrong, especially for large sets of data. Now the summaries should be accurate.
In the latest build 3257 that has just been released now, we have taken it further. Now there is an option to load data for groups on demand, i.e. when the user expands a particular group. There are other improvements as well - for example, summaries can now be displayed either in the header of the group or in the footer or both. In addition, there is an option to hide summaries in the header if a group is expanded (so that the summary is only shown in the footer.
