eYou can group your tasks using by different fields values. When grouped, the task structure (WBS) is replaced by the group structure. This means that the task hierarchy is not shown when items are grouped.

To group using a specific field, make sure it is added as a column using first.  The group feature is in Data drop-down. The groups are marked with selected colors, both, on the task list and on the timeline indicating the earliest start and latest date of the tasks in that group.

Grouping Tasks

You can define define the order of the groups, activate fields to create groups and color code the created groups. If you want to start from scratch, click the "Deactivate all" button.

Coloring groups

The groups will be marked with selected colors, both, on the task list and on the timeline

Multi-level grouping

Multi-level grouping is possible and tasks will be counted in each group. The group structure will be based on the of active grouping elements and the order of grouping elements (fields) determines the group hierarchy.

Task can not be duplicated which means that a task can belong to single group only.

For example, let's group the tasks by Status and Assignee fields:

Sorting Grouped Tasks

Presently, you can't sort tasks once they have been grouped. 

Data Aggregation

The first row is reserved for aggregations and unless you set the it for each column separately it will remain empty. To learn more about configuring Column View and aggregation go to Column Views Gantt.

For example, let's group our tasks first by Issue type field and within this group by Status. The tasks are grouped in you can now collapse the groups which you do not want to analyse. Based on the information displayed we can see that there is only one Feature BPV-6 has a status "In Progress". Let's have a closer look at the Original Estimate column which has two values 6w which is the sum of all the lower level items, in that case the stories but actually the feature was also estimated and its Original estimate is 3w 1d which is the sum of all items in that group. The initial estimate in that case was much less the the bottom up estimate of the stories

Affects

Search box 

When tasks are grouped the serach functionality doesn't filter tasks. Both ABC and JQL modes are affected.