HOVER: Ensure to clear after reparenting all notifications

Signed-off-by: Carlo Savignano <stevewatersy@gmail.com>
Change-Id: I8d3735836952394942f044ebd067d7cc7a82bc2e
HOVER: Fix notification content not being updated

Change-Id: I6f5e95cfff9b78cdabd1d9aa00e0577b0ab78508