Auto-layout changing depending on view as setting on simulator

Question

I am noticing something strange using XCode 9.3.

I have a view with a UIToolBar on the bottom of it. I have set the following constraints:

1. Align Center X to: superview
2. Trailing Space (0): superview
3. Leading Space (0): superview
4. Equal Width: superview
5. Bottom Space (0): superview
6. Height equals 44.

The superview is a UIView.

When I viewAs iPhone 8 and then load an iPhone SE Simulator you can see the pink section on the image is where the toolbar is not satisfying rule 4 above.

However, if I set viewAs iPhone SE, it works perfectly:

Any ideas anyone?

I've done no Vary for Traits.

Answer 1

Trailing Space (0): superview

Leading Space (0): superview

Bottom Space (0): superview

Height equals 44.

You just need these 4 constraints