What are gray constraints in Xcode view hierarchy debug view?

Question

I know what the solid ones are: I created them myself. What about the gray ones? Implicit, maybe via size-to-fit? The gray height conflicts with the solid height. Where do the g

Answer 1

I was facing this issue because I added subviews to UIStackView using addSubview instead of addArrangedSubview. -_-

Answer 2

For me the gray constraints appeared because I was modifying the UIView's size outside the main thread.

Make sure you don't make the same mistake:

DispatchQueue.main.async {
   //modify your view here
}

Answer 3

You are inspecting an object such as a label that has an intrinsic content size. The intrinsic content size generates height and width constraints; that's what intrinsic content size is. The constraints in gray are showing you the constraints that the intrinsic content size generates. If you just look at them, you can see that: they say "content size"!

They are in gray because they are overridden by your explicit constraints (they have a lower priority). But they are still there, and if you were not overriding them, they would take effect (and they would not be gray).