Change the height of the right toolbar

reader/src/main/res/layout/activity_reader.xml

@@ -100,15 +100,16 @@
     </com.kdanmobile.reader.view.HorizontalView>
     <com.kdanmobile.reader.view.HorizontalView
         android:id="@+id/viewGroup_readerActivity_rightToolbar"
-        app:layout_constraintTop_toTopOf="parent"
-        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/toolbar_readerActivity"
+        app:layout_constraintBottom_toTopOf="@+id/viewGroup_readerActivity_bottomToolbar"
         app:layout_constraintRight_toRightOf="parent"
-        android:background="@drawable/bg_reader_tool_bar_right"
         android:layout_width="wrap_content"
-        android:layout_height="wrap_content">
+        android:layout_height="0dp">
         <ScrollView
             android:layout_width="wrap_content"
-            android:layout_height="wrap_content">
+            android:layout_height="wrap_content"
+            android:layout_gravity="center"
+            android:background="@drawable/bg_reader_tool_bar_right">
             <android.support.constraint.ConstraintLayout
                 android:orientation="vertical"
                 android:layout_width="wrap_content"