Application's Task Grouping feature allows us to sort our tasks list on both: Gantt's WBS and the Gantt chart, by a value of an attribute present in WBS Columns. Once we select Task Grouping menu from Data tab, a menu with selection of attributes (values for the grouping purpose) will appear. We can easily change the order of our attribute bars and populate desired checkboxes in these interactive planks.
It is possible to group tasks using only one attribute, yet as the Task Grouping feature is based on Gantt's WBS Columns mechanism, tasks in this mode can be grouped by multiple criteria at the same time. As we already know, it is possible for these grouping criteria to be arranged using drag and drop mechanism, which sets the group order on our chart.
Once we use this feature and our Tasks are divided into groups, we will be able to see a number on each groups tab. This number is, of course, a number of Tasks within each group category.