Fix bug: workspace screens not being rendered in spring-loaded mode

Bug # 4024334
diff --git a/src/com/android/launcher2/Workspace.java b/src/com/android/launcher2/Workspace.java
index 5a230eb..7956b45 100644
--- a/src/com/android/launcher2/Workspace.java
+++ b/src/com/android/launcher2/Workspace.java
@@ -1181,8 +1181,9 @@
             final int pageCount = getChildCount();
             final long drawingTime = getDrawingTime();
             for (int i = 0; i < pageCount; i++) {
-                final View page = (View) getChildAt(i);
-                if (page.getVisibility() == VISIBLE && page.getAlpha() != 0f) {
+                final CellLayout page = (CellLayout) getChildAt(i);
+                if (page.getVisibility() == VISIBLE
+                        && (page.getAlpha() != 0f || page.getBackgroundAlpha() != 0f)) {
                     drawChild(canvas, page, drawingTime);
                 }
             }