BUG #14048. Selected rows weren't cleared when selection changed.

Selected rows weren't cleared when selection changed, rather the notification
that the rows were cleared wasn't sent. Fixed that. Also fixed the random header
highliting issue (the header for the spreadsheet view would occassionaly go
*bold* as the selection changed.

Change-Id: Id49a79f01c54101fbbbbc0e376747a084e3932c9
Merge topic '14045_fix_selection_speadsheet_view_bug' into next

d006336 BUG #14048. Selected rows weren't cleared when selection changed.