Open Radar

 
Summary:
After invoking `registerForPreviewingWithDelegate:sourceView:` on a view, the view's `touchesEnded:withEvent:` will get invoked twice instead of once after a long-press.

Steps to Reproduce:
1. Call `registerForPreviewingWithDelegate:sourceView:` on source view X
2. On the device, long press on view X
3. When releasing view X, its `touchesEnded:withEvent:` method will be called twice

Expected Results:
`touchesEnded` should only be called once.

Actual Results:
`touchesEnded` called twice in a row.

Logs as copied from the test project -- note that `touchesBegan` is only called once as expected, but `touchesEnded` is invoked twice. 

2015-09-29 21:17:41.455 TouchTester[43302:4211441] touchesBegan
2015-09-29 21:17:42.307 TouchTester[43302:4211441] touchesEnded
2015-09-29 21:17:42.307 TouchTester[43302:4211441] touchesEnded


Version:
iOS 9.0, iOS 9.0.1

Notes:


Configuration:
iPhone 6s

Attachments:
[Sample code copied below:]

```
#import "ViewController.h"

@interface TestView : UIView

@end

@interface ViewController () <UIViewControllerPreviewingDelegate>

@end

@implementation ViewController
{
    TestView *_view;
}

- (void)viewDidLoad
{
    [super viewDidLoad];

    _view = [[TestView alloc] initWithFrame:CGRectInset(self.view.bounds, 40, 40)];
    _view.backgroundColor = [UIColor grayColor];
    _view.autoresizingMask = UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleWidth;
    [self.view addSubview:_view];

    [self registerForPreviewingWithDelegate:self sourceView:_view];
}

- (nullable UIViewController *)previewingContext:(id <UIViewControllerPreviewing>)previewingContext viewControllerForLocation:(CGPoint)location
{
    return nil;
}

- (void)previewingContext:(id <UIViewControllerPreviewing>)previewingContext commitViewController:(UIViewController *)viewControllerToCommit
{
}

@end

@implementation TestView

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    [super touchesBegan:touches withEvent:event];
    NSLog(@"touchesBegan");
}

- (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    [super touchesEnded:touches withEvent:event];
    NSLog(@"touchesEnded");
}

@end
```