title: ScrollView not scrolling with ConstraintLayout and guideline
body: <p>I have to make a layout with an image on top and text above. The images height has to be 40% of the root layout height. The text has variable height. Therefore the whole thing has to be put in a ScrollView.</p>
  
  <p>Here is my code:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:background="@color/colorTutorialGrey"
  &gt;
  
  
  &lt;ScrollView
      android:layout_width="0dp"
      android:layout_height="0dp"
      app:layout_constraintTop_toTopOf="parent"
      app:layout_constraintLeft_toLeftOf="parent"
      app:layout_constraintRight_toRightOf="parent"
      app:layout_constraintBottom_toBottomOf="parent"
      android:fillViewport="true"
      &gt;
  
      &lt;android.support.constraint.ConstraintLayout
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          &gt;
  
          &lt;android.support.constraint.Guideline
              android:id="@+id/guideline"
              android:orientation="horizontal"
              android:layout_width="match_parent"
              android:layout_height="wrap_content"
              app:layout_constraintGuide_percent="0.4"/&gt;
  
          &lt;ImageView
              android:id="@+id/tutorial_image"
              android:layout_width="0dp"
              android:layout_height="0dp"
              android:scaleType="centerCrop"
              app:layout_constraintTop_toTopOf="parent"
              app:layout_constraintLeft_toLeftOf="parent"
              app:layout_constraintRight_toRightOf="parent"
              app:layout_constraintBottom_toTopOf="@+id/guideline"
              tools:src="@drawable/splash_bg"
              /&gt;
  
          &lt;LinearLayout
              android:orientation="vertical"
              android:layout_width="0dp"
              android:layout_height="wrap_content"
              android:padding="32dp"
              app:layout_constraintTop_toBottomOf="@id/guideline"
              app:layout_constraintLeft_toLeftOf="parent"
              app:layout_constraintRight_toRightOf="parent"
              &gt;
  
              &lt;TextView
                  android:id="@+id/tutorial_title"
                  style="@style/Tutorial.Title"
                  android:layout_width="match_parent"
                  android:layout_height="wrap_content"
                  tools:text="Alle Neuerungen der App auf einen Blick"
                  /&gt;
  
              &lt;TextView
                  android:id="@+id/tutorial_description"
                  style="@style/Tutorial.Description"
                  android:layout_width="match_parent"
                  android:layout_height="wrap_content"
                  tools:text="Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. no sea takimata sanctus est Lorem ipsum dolor sit amet. no sea takimata sanctus est Lorem ipsum dolor sit amet. no sea takimata sanctus est Lorem ipsum dolor sit amet. no sea takimata sanctus est Lorem ipsum dolor sit amet. no sea takimata sanctus est Lorem ipsum dolor sit amet. no sea takimata sanctus est Lorem ipsum dolor sit amet. no sea takimata sanctus est Lorem ipsum dolor sit amet. no sea takimata sanctus est Lorem ipsum dolor sit amet. no sea takimata sanctus est Lorem ipsum dolor sit amet. no sea takimata sanctus est Lorem ipsum dolor sit amet. no sea takimata sanctus est Lorem ipsum dolor sit amet. no sea takimata sanctus est Lorem ipsum dolor sit amet. no sea takimata sanctus est Lorem ipsum dolor sit amet. no sea takimata sanctus est Lorem ipsum dolor sit amet."
                  /&gt;
  
          &lt;/LinearLayout&gt;
  
      &lt;/android.support.constraint.ConstraintLayout&gt;
  
  &lt;/ScrollView&gt;
  &lt;/android.support.constraint.ConstraintLayout&gt;
  </code></pre>
  
  <p>The layout is like it is desired, but as soon as i put in the Guideline, the ScrollView does not scroll anymore.</p>
  
  <p>What mistake do i make and how can i achieve the desired layout and behaviour?</p>