I tried to trash one event of a recurring event and it trashed all of them.
If you’re doing that from the list of events admin-side then that is expected behaviour – it should however be possible to do it from within the actual event editor for the instance of an event you wish to delete.
The screen turned dark and I could see the circle going around on the update button but it never finished and the screen stayed dark.
It sounds like you might be describing a known problem and if so we’ve got a fix in our list of Useful Code Snippets (over on the right) that might tide you over until it is addressed in a future maintenance release:
Fix for Update Recurring Events Dialog
Does that help here?