Organisations inherit workflows from their aggregator or parent organisation. In addition everyone has 'legacy' workflows that were transferred from 1.0. Often some of these workflows are not required. This feature makes it possible to hide workflows that are not needed.
This feature enables hiding of workflows for all users in a single organisation. Individual settings for workflow hiding are not available. Only admin users can access this feature.
Go to Settings >> Process/Workflows
Select the 'hide' switch on the workflow that needs to be hidden on the UI and move to the right.
Check if the workflow is hidden
To unhide reverse this process.
Note that deals in hidden workflows can still be found via API and via search function.

