iPad: IBAction for UIButton responds on iPhone device, not on iPad

I have taken over the development and maintenance of a production iOS application being used mostly on the iPhone but also on the iPad. We found a specific UIButton that will respond as expected on the iPhone (device & simulator) but does not respond on the iPad 开发者_高级运维(device & simulator).

I am lost on where to start debugging this item. Any suggestion? Thanks in advance.

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Kinda late to this party, but I had this symptom as well. The problem was my button was embedded in a view that had has height of 44 in IB, but when running shrunk to 0. It's contents rendered just fine, which made it hard to track down. Once I added a height constraint to the containing view, my UIButton now responds as expected. My guess is that the shorter height running on the iPad squished my containing view.

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So it looks like this one was pretty easy for me.

[self.view bringSubviewToFront: button]; //moves the button above other subviews
[button setNeedsDisplay]; //ensure the button is redrawn

I am still not sure why this only happens when running on an iPad, but this fixed my problem.