Using a NSSavePanel from Qt for a native save dialog

The code below works most of the time, maybe a more experienced Objective C++ programmer can help me:

Issue 1: When called from specific menu QActions, the system starts to animate the dialog into existence and then automatically closes it before it is drawn full size; the return code is -1000. For other specific actions it always works correctly.

Issue 2: I try to disable the Tags field but it still shows on Mavericks. If I remove the if statement the tags field is hidden on Mavericks but the program crashes on Lion.

// Use native dialog to save a fileQString GetCocoaSaveFile(const QString &prompt, const QString &source_dir, const QString &filename){  QString selected_file;  NSSavePanel *panel = [NSSavePanel savePanel];  [panel setFloatingPanel:YES];  if([panel respondsToSelector:@selector(setShowsTagField)])  // Only available on 10.9+    [panel setShowsTagField:NO];  NSString *title_ns = [[NSString alloc]initWithUTF8String:prompt.toUtf8().data()];  [panel setTitle:title_ns];  NSString *path_ns = [[NSString alloc]initWithUTF8String:source_dir.toUtf8().data()];  NSURL *directory_url = [[NSURL alloc]initFileURLWithPath:path_ns];  [panel setDirectoryURL:directory_url];  NSString *default_ns = nil;  if(!filename.isEmpty())  {    default_ns = [[NSString alloc]initWithUTF8String:filename.toUtf8().data()];    [panel setNameFieldStringValue:default_ns];  }  NSInteger result = [panel runModal];  if(result == NSFileHandlingPanelOKButton)  {    NSURL *result_url = [panel URL];    NSString *path_sel = [result_url path];    selected_file = QString::fromUtf8([path_sel UTF8String]);  }  if(default_ns) [default_ns release];  [directory_url release];  [path_ns release];  [title_ns release];  return(selected_file);}

I'm using Qt 5.2.0 if that is relevant.