Most objects can be deleted by double-clicking them to open the object properties, and then clicking the ERASE button in the dialog box that appears.
You can also delete an object by pressing the delete key on the keyboard when the object is selected on the screen.
When an Object is deleted Simul8 redraws some of the Routing Arrows. For example, if you have an Activity linked to a Queue that is linked to another Activity and the Queue is deleted, Simul8 will draw a link between the two Activities. However, if your process has a Queue linked to an Activity that is linked to another Queue, and the Activity is deleted, then Simul8 will not draw any new links. This is because you cannot link two Queues together, but you can link two Activities together. So Simul8 looks at the objects that are left after the deletion and will only draw in routing arrows if the link is valid.