Missing field with the addition of constraints as to add?

Used to be able to add the constraints, now this field has become inactive and don't know how to activate it.
Can who faced such problem?

You need to put a segment control on constraint that it was tied to the navigation bar.

5e99dbd09a0ba647330159.png

5e99dc2d9e218605046905.png
April 19th 20 at 12:34
0 answer

Find more questions by tags SwiftiOS