Functionality is limited to the abilities of
current index which is not updated and is
generated only at project open.
Search box temporarily doesn't allow to "Search again".

Change-Id: Id1047f27ad0aafc901f06aa51ad38ceab95eaebb
Reviewed-by: Marco Bubke <marco.bubke@qt.io>
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@qt.io>