Q:

Layout align center under ConstraintLayout in Android Studio 2.3.1

In Android Studio 2.3.1 built on 2017 April 1. I could not center my 2nd LinearLayout over my 1st LinearLayout.
Here is my second layout:
android:layout_width="wrap_content"
android:layout_height="wrap_content"

android:layout_centerVertical="true"
android:layout_centerHorizontal="true"
android:layout_gravity="center_horizontal"
android:gravity="center_vertical|center_horizontal|center"
android:orientation="vertical"
android:padding="30dp"

A:

I had to go to Component Tree > RIGHT CLICK on my2ndlayout 

choose "Center Horizontally" and "Center Vertically" !!

