Fix story reply mention fragment from taking over screen.

app/src/main/java/org/thoughtcrime/securesms/stories/viewer/reply/group/StoryGroupReplyFragment.kt

@@ -88,6 +88,7 @@ class StoryGroupReplyFragment :
 
   private lateinit var recyclerView: RecyclerView
   private lateinit var composer: StoryReplyComposer
+  private var currentChild: StoryViewsAndRepliesPagerParent.Child? = null
 
   override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
     SignalExecutors.BOUNDED.execute {
@@ -204,7 +205,12 @@ class StoryGroupReplyFragment :
   }
 
   override fun onPageSelected(child: StoryViewsAndRepliesPagerParent.Child) {
-    recyclerView.isNestedScrollingEnabled = child == StoryViewsAndRepliesPagerParent.Child.REPLIES
+    currentChild = child
+    updateNestedScrolling()
+  }
+
+  private fun updateNestedScrolling() {
+    recyclerView.isNestedScrollingEnabled = currentChild == StoryViewsAndRepliesPagerParent.Child.REPLIES && !(mentionsViewModel.isShowing.value ?: false)
   }
 
   private var resendBody: CharSequence? = null
@@ -302,6 +308,8 @@ class StoryGroupReplyFragment :
     mentionsViewModel.selectedRecipient.observe(viewLifecycleOwner) { recipient ->
       composer.input.replaceTextWithMention(recipient.getDisplayName(requireContext()), recipient.id)
     }
+
+    mentionsViewModel.isShowing.observe(viewLifecycleOwner) { updateNestedScrolling() }
   }
 
   private fun ensureMentionsContainerFilled() {

app/src/main/res/layout/stories_group_replies_fragment.xml

@@ -30,6 +30,16 @@
         app:layout_constraintVertical_bias="0"
         tools:itemCount="0" />
 
+    <androidx.fragment.app.FragmentContainerView
+        android:id="@+id/mentions_picker_container"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        app:layout_constraintBottom_toTopOf="@+id/composer"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent"
+        app:layout_constraintVertical_bias="1" />
+
     <org.thoughtcrime.securesms.stories.viewer.reply.composer.StoryReplyComposer
         android:id="@+id/composer"
         android:layout_width="match_parent"

app/src/main/res/layout/stories_reply_to_story_composer.xml

@@ -7,11 +7,6 @@
     android:layout_gravity="bottom"
     android:orientation="vertical">
 
-    <androidx.fragment.app.FragmentContainerView
-        android:id="@+id/mentions_picker_container"
-        android:layout_width="match_parent"
-        android:layout_height="wrap_content" />
-
     <include layout="@layout/stories_reply_to_story_composer_content" />
 
     <org.thoughtcrime.securesms.components.emoji.MediaKeyboard