Redrawing a SFAuthorizationPluginView

I'm writing a custom AuthenticationPlugin which has some dynamic content (currently in the form of labels). I'd like to be able to update the labels in response to events.

Assuming the following declarations:

• parent = SFAuthorizationPluginView (subclass)
  • view = NSView (subclass)
    • NSTextField *label = ...

I edit the label text as follows (note: this may be executed from the background dispatch queue):
[label setStringValue:@"new text"];

I then try to force an update using the following:

• [label setNeedsDisplay:YES];
• dispatch_async(dispatch_get_main_queue(), ^{ [label setNeedsDisplay:YES]; });
• [label display];
• dispatch_async(dispatch_get_main_queue(), ^{ [label display]; });
• [[label cell] update];
• dispatch_async(dispatch_get_main_queue(), ^{ [[label cell] update]; });
• [[label cell] needsDisplay];
• dispatch_async(dispatch_get_main_queue(), ^{ [[label cell] needsDisplay]; });
• [view setNeedsDisplay:YES];
• dispatch_async(dispatch_get_main_queue(), ^{ [view setNeedsDisplay:YES]; });
• [self updateView];
• dispatch_async(dispatch_get_main_queue(), ^{ [self updateView]; });
• [self displayView]
• dispatch_async(dispatch_get_main_queue(), ^{ [self displayView]; });

However, I get a mixture of no action and flickering grey screen (indicating I've caused an exception).

Any ideas? (Note: I'll be editing this question as I try various options)

I think all you need to do is put the update of the label in the main queue code like this:

dispatch_async(dispatch_get_main_queue(), ^{
 label.text = "Hello World!";
});