i create a project with a framework target and a app target.

in the framework target, i create a class called MyButton inherit the UIButton class.

in the app target, i use the stroryboard and put a UIButton on it,now i use the MyButton class in the interface. 

[![](https://i.stack.imgur.com/NwhSs.png)](https://i.stack.imgur.com/NwhSs.png)

the question is when i set framework target's mach-o type with default option Dynamic library ,i can build and run success.
but when i change the mach-o type with Static library option,i can build success but run failed.the error message is "Unknown class MyButton in Interface Builder file."

[![](https://i.stack.imgur.com/UJQhC.png)](https://i.stack.imgur.com/UJQhC.png)

[![](https://i.stack.imgur.com/yE5UU.png)](https://i.stack.imgur.com/yE5UU.png)

[![](https://i.stack.imgur.com/1kpii.png)](https://i.stack.imgur.com/1kpii.png)

i am confused with it,anyone can explain it please.

the test demo is here. <https://github.com/george-luofz/Test_useFrameworkInXib.git>