Mastering UI Development with Unity

Control Child Size

These Control Child Size options allow the automatic layout to override the current Width or Height of the child objects. If you select it without selecting the corresponding Child Force Expand property, your child objects will no longer be visible (unless it has a Layout Element component with Preferred Width specified).

If you do not set this property, it is possible that the children will draw outside of the parent's Rect Transform, that is, if too many children exist.

This property changes the width and height property of the child objects' Rect Transforms. So, if you select and then deselect it, the children will not go back to their original sizes. You will have to either use Edit | Undo (Ctrl + Z) or manually reset ...