You all are mixing subjects: what has to do SCANNING in a thread titled UPDATES?
And the issue about Automatic Scan has already been treated in another thread: in Automatic Scan is not visible the OK button but the scan, as usually happens in many contexts, starts just by pressing GREEN.
And, as I said in that thread, the Automatic Scan submenu, is the most useless of all: why don't you simply use the Manual Scan menu?
Why on earth someone should launch a complete scan, over every sources?
Are you scan-aholic? A complete scan it's something you may want do to just twice or three times a year: then is more clever to perform limited scans just consulting specialized website about new channels.