ios - [UIBarButtonItem _isAncestorOfFirstResponder]: unrecognized selector sent to instance -

this code works in 1 app , crashes in message:

[uibarbuttonitem _isancestoroffirstresponder]: unrecognized selector sent instance 

if comment magical record code can see method runs ok.

- (void)viewdidload{     [super viewdidload];      uibarbuttonitem *addbutton = [[uibarbuttonitem alloc]initwithbarbuttonsystemitem:uibarbuttonsystemitemadd target:self action:@selector(addnote:)];     self.navigationitem.rightbarbuttonitem = addbutton; }   - (ibaction)addnote:(id)sender{     nslog(@"%s",__pretty_function__);      nsmanagedobjectcontext *localcontext = [nsmanagedobjectcontext mr_contextforcurrentthread];     note *note = [note mr_createincontext:localcontext];     nsdate *now = [nsdate date];     note.date = now;     note.person = _person;     [localcontext mr_savewithoptions:mrsavesynchronously completion:^(bool success, nserror *error) {          uistoryboard *sb = [uistoryboard storyboardwithname:nsbundle.mainbundle.infodictionary[@"uimainstoryboardfile"] bundle:nsbundle.mainbundle];         noteviewcontroller *vc = [sb instantiateviewcontrollerwithidentifier:@"noteviewcontroller"];         vc.note = note;          [self.navigationcontroller pushviewcontroller:vc animated:yes];     }]; }   - (void)viewwillappear:(bool)animated {     [super viewwillappear:animated];      uilabel *noresultslabel = [[uilabel alloc]initwithframe:cgrectmake(0, 0, self.tableview.bounds.size.width, self.tableview.bounds.size.width)];     noresultslabel.textcolor = [uicolor colorwithwhite:0.557 alpha:1.000];     noresultslabel.font = [uifont boldsystemfontofsize:35];     noresultslabel.textalignment = nstextalignmentcenter;     noresultslabel.text = nslocalizedstring(@"no notes", nil);     self.tableview.nxev_emptyview = noresultslabel;      self.fetchedresultscontroller.delegate = self;     [self.fetchedresultscontroller performfetch:nil];     [self.tableview reloaddata]; }  - (void)viewwilldisappear:(bool)animated {     [super viewwilldisappear:animated];     _fetchedresultscontroller.delegate = nil; }  #pragma mark - fetched results controller - (void)dealloc {     nslog(@"%s",__pretty_function__);     self.fetchedresultscontroller.delegate = nil;     self.fetchedresultscontroller = nil; }  - (nsfetchedresultscontroller *)fetchedresultscontroller {     if (_fetchedresultscontroller != nil) {         return _fetchedresultscontroller;     }      nspredicate *predicate = [nspredicate predicatewithformat:@"person == %@", _person];      self.fetchedresultscontroller = [note mr_fetchallgroupedby:@"source" withpredicate:predicate sortedby:@"source,date" ascending:yes delegate:self];      nserror *error = nil;     if (![self.fetchedresultscontroller performfetch:&error]) {         nslog(@"unresolved error %@, %@", error, [error userinfo]);         abort();     }      return _fetchedresultscontroller; }  - (void)controllerwillchangecontent:(nsfetchedresultscontroller *)controller {     [self.tableview beginupdates]; }  - (void)controller:(nsfetchedresultscontroller *)controller didchangesection:(id <nsfetchedresultssectioninfo>)sectioninfo            atindex:(nsuinteger)sectionindex forchangetype:(nsfetchedresultschangetype)type {     switch(type) {         case nsfetchedresultschangeinsert:             [self.tableview insertsections:[nsindexset indexsetwithindex:sectionindex] withrowanimation:uitableviewrowanimationfade];             break;          case nsfetchedresultschangedelete:             [self.tableview deletesections:[nsindexset indexsetwithindex:sectionindex] withrowanimation:uitableviewrowanimationfade];             break;     } }  - (void)selectcreatedrowatindexpath:(nsindexpath *)indexpath{     [self.tableview selectrowatindexpath:indexpath animated:yes scrollposition:uitableviewscrollpositionmiddle]; } - (void)controller:(nsfetchedresultscontroller *)controller didchangeobject:(id)anobject        atindexpath:(nsindexpath *)indexpath forchangetype:(nsfetchedresultschangetype)type       newindexpath:(nsindexpath *)newindexpath {     uitableview *tableview = self.tableview;      switch(type) {         case nsfetchedresultschangeinsert:             [tableview insertrowsatindexpaths:[nsarray arraywithobject:newindexpath] withrowanimation:uitableviewrowanimationautomatic];             break;          case nsfetchedresultschangedelete:             [tableview deleterowsatindexpaths:[nsarray arraywithobject:indexpath] withrowanimation:uitableviewrowanimationautomatic];             break;          case nsfetchedresultschangeupdate:             [self configurecell:(notecell *)[tableview cellforrowatindexpath:indexpath] atindexpath:indexpath];             break;          case nsfetchedresultschangemove:             [tableview deleterowsatindexpaths:[nsarray arraywithobject:indexpath] withrowanimation:uitableviewrowanimationautomatic];             [tableview insertrowsatindexpaths:[nsarray arraywithobject:newindexpath]withrowanimation:uitableviewrowanimationautomatic];             break;     } }  - (void)controllerdidchangecontent:(nsfetchedresultscontroller *)controller {     [self.tableview endupdates];     [self.tableview reloaddata]; }  - (nsstring *)tableview:(uitableview *)tableview titleforheaderinsection:(nsinteger)section{     id <nsfetchedresultssectioninfo> sectioninfo = [self.fetchedresultscontroller sections][section];     if (sectioninfo.name.intvalue == 0) {         return nslocalizedstring(@"not secret", @"notes");     }else return nslocalizedstring(@"secret", @"notes"); }   - (nsinteger)numberofsectionsintableview:(uitableview *)tableview {     return [[self.fetchedresultscontroller sections] count]; }   - (nsinteger)tableview:(uitableview *)tableview numberofrowsinsection:(nsinteger)section {     id <nsfetchedresultssectioninfo> sectioninfo = [[self.fetchedresultscontroller sections] objectatindex:section];     return [sectioninfo numberofobjects]; }  - (uitableviewcell *)tableview:(uitableview *)tableview cellforrowatindexpath:(nsindexpath *)indexpath {     static nsstring *cellidentifier = @"note cell";      notecell *cell = (notecell *)[tableview dequeuereusablecellwithidentifier:cellidentifier forindexpath:indexpath];     [self configurecell:cell atindexpath:indexpath];      return cell; } - (void)configurecell:(notecell *)cell atindexpath:(nsindexpath *)indexpath {     note *note = [self.fetchedresultscontroller objectatindexpath:indexpath];      cell.datelabel.text = [[czdateformattercache mainqueuecache] localizedstringfromdate:note.date datestyle:kcfdateformatterlongstyle timestyle:kcfdateformattershortstyle];      if (note.note.length > 0) {         cell.notelabel.text = note.note;     } else {         cell.notelabel.text = nslocalizedstring(@"new note", nil);     }      cell.rateview.rate = [note.trustworthy intvalue];     nslog(@"note.trustworthy intvalue %i", [note.trustworthy intvalue]);      cell.rateview.backgroundcolor = [uicolor clearcolor];     cell.backgroundcolor = [uicolor whitecolor]; }  - (void)tableview:(uitableview *)tableview commiteditingstyle:(uitableviewcelleditingstyle)editingstyle forrowatindexpath:(nsindexpath *)indexpath {     if (editingstyle == uitableviewcelleditingstyledelete) {         [magicalrecord saveusingcurrentthreadcontextwithblock:^(nsmanagedobjectcontext *localcontext) {             [[self.fetchedresultscontroller objectatindexpath:indexpath] mr_deleteincontext:localcontext];         } completion:^(bool success, nserror *error) {             //         }];     } }  - (bool)tableview:(uitableview *)tableview canmoverowatindexpath:(nsindexpath *)indexpath {     return no; }  #pragma mark - segue - (void)prepareforsegue:(uistoryboardsegue *)segue                  sender:(id)sender {     if ([segue.identifier isequaltostring:@"note segue"]) {         nslog(@"%s",__pretty_function__);         nsindexpath *indexpath = [self.tableview indexpathforselectedrow];         note *note = [[self fetchedresultscontroller] objectatindexpath:indexpath];         noteviewcontroller *anvc = segue.destinationviewcontroller;         anvc.note = note;     } } 

ok, problem in second view controller. found occasionally.

i used uibarbuttonitem custom view navigation bar titleview.