When I try to delete a flow in Flow Designer I just get a gray screen and everything seems locked up.
All versions of xMatters On Demand.
Look for any popup or ad blockers in your browser and disable them for the xMatters web user interface.
An overlay or popup blocker is preventing a warning screen or modal from coming up. While it looks like things are hanging, it's actually just a dialog box that needs you to confirm deletion of the flow.