Place buttons and labels on top of UIImageView in Xcode 6

I'm new to iOS development and I'm just getting my way around Xcode 6 working with Swift, but I'm hitting small blocks here and there so please understand why question may be very basic.

My issue is I have a background image (UIImageView) which is placed within a View within a ViewController. All I want is to be able to drag and drop other type of objects like buttons or labels on top in the designer section. When I have the designer view I see these buttons and labels visible on top of the UIImageView, but when I run the project in the iPhone simulator all these objects disappear and I just see the background image (UIImageView). Is there something I'm missing here?

Thanks in advance.