Apr 07, 2014 - 11:29 PM
If a scenario has been published to TFS as work item and after that this scenario is either modified or deleted in diagram. In this case previous scenario has been obsoleted and does no longer exist in a diagram. For such obsoleted scenarios, 'Delete' icon will be enabled.
If you see in image above, for selected obsolete scenario, no path is highlighed in diagram (on canvas). This means that this scenario does not exist in diagram.