Change MediaBox Stamp UI

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

@@ -63,7 +63,7 @@
 
     <android.support.v7.widget.RecyclerView
         android:id="@+id/recyclerView_shapeCustom"
-        android:layout_width="match_parent"
+        android:layout_width="wrap_content"
         android:layout_height="0dp"
         app:layout_constraintBottom_toBottomOf="parent"
         app:layout_constraintLeft_toLeftOf="parent"