The blue focus ring outside NSTextField missing? - xcode

Question

In normal case, a blue retangle would appear outside a NSTextField object which becomes the first responder, like this image:
link for Normal Case
However, I got a NSTextField that have no the blue border outside. Why is that?
Here is how it happerns:
1> I create a typical MAC OS app.
2> I switch app's subview by calling the corresponding view's addSubview: and removeFromSuperview methods.
3> In one subview (which is actually the image referenced above) I click the "Next" button. Its action is something like this (defined in the subview's controller .m file):
- (IBAction)actionNextClicked:(id)sender{
//_hdlThreadNext is a NSThread object
[[_hdlThreadNext alloc] initWithTarget:self selector#selector(threadNext:) object:nil];
[_hdlThreadNext start];
}
And the thread is like:
- (void)threadNext:(id)sender{
#autoreleasepool{
BOOL success;
[CATransation begin];
/* send username and password and decrypt responce */
... // balabala... and set "success"
if (success){
[[self view] removeFromSuperview];
[self sendMessageToSuperview:#"Add Next View"]; // Superview's method, telling superview to call addSubview: to add another subview
}
else{
/* Nothing special to do */
}
[CATransation commit];
}
}
4> The subview switch to another one. Its combo view seemed to be OK: image for combo view
But the other NSTextView's blue border would NOT appear anymore!
Does Any guy know what wrong I had done? Thank you very much!

Answer 1

Perhaps I did totally wrong programming, so that few people met this problem.
I found a way to solve this problem. I mentioned that all (or most of?) the graphic changes should be done in main thread in a blog. Therefore I change the "if(success)" as:
if(success){
dispatch_async(dispatch_get_main_queue()' ^{
[[self view] removeFromSuperview];
[self sendMessageToSuperview:#"Add Next View"];
});
}
Solved, the focus rings come back.