there should be an extra action to remove the object from the workspace starting from the details of that object. If you decide that a newly created object should not be stored in the database, you have the possibility to delete the object from workspace. Unfortunately you have to first locate your object in the workspace, and if there are several newly created objects in the workspace it's not that efficient.
Starting from your CAD application, you can easily go to the details page of this object, by selecting 'view server properties', but there is no action 'remove from workspace' available in the actions menu.
best regards,
Stijn
