android: fix part sidebar not executing an "part change" event..

Change-Id: I8f984ad050d8124164617f67f5ea7fa511e50f55

android/experimental/LOAndroid3/res/layout/activity_main.xml

@@ -18,6 +18,18 @@
             android:layout_height="fill_parent"
             android:layout_weight="1"/>
 
+        <RelativeLayout
+            android:id="@+id/loadingPanel"
+            android:layout_width="match_parent"
+            android:layout_height="match_parent"
+            android:gravity="center" >
+
+            <ProgressBar
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:indeterminate="true" />
+        </RelativeLayout>
+
         <View
             android:layout_width="match_parent"
             android:layout_height="match_parent"/>