Open DevTest Portal to visualize the virtual services deployed to the VSE - under Monitor/Virtual Service Environments/VSE.
Filter the list of VSMs on one of the columns - Category, Name, Resource/ Type, Status or Group.
Then select the checkbox to select ALL the filtered services and perform a bulk action such as start, stop, or remove.
It affects all services, not just the filtered virtual services.
DevTest 9.5.1.DevTest 10.0
This is a known issue that is fixed with DevTest on release 10.1.