[Zubersoft]

You cannot delete while using the multi-selection dialog (although enough people seem to be confused by this that I will probably add support for it). Close the dialog, then just long press on the sh entry (the one with a blue box) in the field. You'll see an option to delete the entry there. Alternatively, go to Settings->Library Settings->Tab Selection and Order, add the Source Types tab, then long press the Sh entry on that tab and tap "Delete" at the top of the screen.

Mike