Fix index out of bounds

Change-Id: Id288c01ab7e39fb16e7247030dbb76183436cb79
diff --git a/src/com/android/launcher2/Folder.java b/src/com/android/launcher2/Folder.java
index 3411f27..0470e41 100644
--- a/src/com/android/launcher2/Folder.java
+++ b/src/com/android/launcher2/Folder.java
@@ -219,6 +219,7 @@
             ShortcutInfo child = (ShortcutInfo) children.get(i);
             createAndAddShortcut(child);
         }
+        mItemsInvalidated = true;
         mInfo.addListener(this);
     }