Fixed crash while editing, creating, or deleting messages.
Fixed crash while switching or closing windows.
Fixed problem checking and unchecking addresses in MySQL groups.
Fixed problem where a custom column could appear twice.
Fixed problem where sorting an address group would cause problems with address deletion.
Fixed crash when viewing the File menu.
Preview window now automatically selects the first address when previewing for the first time.
Double-clicking anywhere in an address table cell begins editing for that cell.