ios7 - clear text UISearchBar -

i have uisearchbar odd behaviour (ios 7). these steps take:

1) search , select result table.

2) clear search text code (either line)

-(void) tableview:(uitableview *)tableview         didselectrowatindexpath:(nsindexpath *)indexpath  {    [[[self searchdisplaycontroller] searchbar] settext:nil];        [[[self searchdisplaycontroller] searchbar] settext:@""];    //other stuff } 

3) second search. no results shown unless first hit "clear button" inside search field. after hitting "x", behaviour returns normal.

how supposed clear search string after user selects 1 of search results?