Use product backlog controls in Azure Boards
Azure DevOps Services | Azure DevOps Server 2020 | Azure DevOps Server 2019 | TFS 2018 - TFS 2013
Once you've defined your product backlog, you can use the following controls to change or filter the view.
Important
If you turn the In Progress control off, then items that are in the Active, Committed, or Resolved states or in the In Progress category state won't appear in the backlog.
Icon or Link
Control
Function
Backlog
Board
Forecast
Mapping
Parents
In progress items
Email a copy of your backlog
Filter
Settings
/ 
Full screen mode
Enter or exit full screen mode
/ 
Expand/Collapse
Expand or collapse one level of the tree hierarchy
Note
Even if you have show parents turned on, the Create Query and Email controls will only list items at the currently selected level.