iPad keyboard will not dismiss if modal ViewController presentation style is UIModalPresentationFormSheet

This has been classified as "works as intended" by Apple engineers. I filed a bug for this a while back. Their reasoning is that the user is often going to be entering data in a modal form so they are trying to be "helpful" and keep the keyboard visible where ordinarily various transitions within the modal view can cause the keyboard to show/hide repeatedly.

edit: here is the response of an Apple engineer on the developer forums:

Was your view by any chance presented with the UIModalPresentationFormSheet style? To avoid frequent in-and-out animations, the keyboard will sometimes remain on-screen even when there is no first responder. This is not a bug.

This is giving a lot of people problems (myself included) but at the moment there doesn't seem to be a way to work around it.

UPDATE:

In iOS 4.3 and later, you can now implement `-disablesAutomaticKeyboardDismissal' on your view controller to return NO:

- (BOOL)disablesAutomaticKeyboardDismissal {
    return NO;
}

This fixes the issue.

Be careful if you are displaying the modal with a UINavigationController. You then have to set the disablesAutomaticKeyboardDismissal on the navigation controller and not on the view controller. You can easily do this with categories.

File: UINavigationController+KeyboardDismiss.h

#import <Foundation/Foundation.h>

@interface UINavigationController (KeyboardDismiss)

- (BOOL)disablesAutomaticKeyboardDismissal;

@end

File: UINavigationController+KeyboardDismiss.m

#import "UINavigationController+KeyboardDismiss.h"

@implementation UINavigationController(KeyboardDismiss)

- (BOOL)disablesAutomaticKeyboardDismissal
{
    return NO;
}

@end

Do not forget to import the category in the file where you use the UINavigationController.

In the view controller that is presented modally, just override disablesAutomaticKeyboardDismissal to return NO:

- (BOOL)disablesAutomaticKeyboardDismissal {
    return NO;
}