--- a/gfx/layers/wr/WebRenderCommandBuilder.cpp
+++ b/gfx/layers/wr/WebRenderCommandBuilder.cpp
@@ -4,16 +4,17 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "WebRenderCommandBuilder.h"
 
 #include "BasicLayers.h"
 #include "mozilla/AutoRestore.h"
 #include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/Logging.h"
 #include "mozilla/gfx/Types.h"
 #include "mozilla/layers/ClipManager.h"
 #include "mozilla/layers/ImageClient.h"
 #include "mozilla/layers/WebRenderBridgeChild.h"
 #include "mozilla/layers/WebRenderLayerManager.h"
 #include "mozilla/layers/IpcResourceUpdateQueue.h"
 #include "mozilla/layers/SharedSurfacesChild.h"
 #include "mozilla/layers/SourceSurfaceSharedData.h"
@@ -741,16 +742,17 @@ struct DIGroup
       }
 
       if (mInvalidRect.Contains(bounds)) {
         GP("Wholely contained\n");
         BlobItemData* data = GetBlobItemData(item);
         data->mInvalid = false;
       } else {
         BlobItemData* data = GetBlobItemData(item);
+        gfxCriticalError() << "DisplayItem" << item->Name() << "should be invalid";
         // if the item is invalid it needs to be fully contained
         MOZ_RELEASE_ASSERT(!data->mInvalid);
       }
 
       nsDisplayList* children = item->GetChildren();
       if (children) {
         GP("doing children in EndGroup\n");
         aGrouper->PaintContainerItem(this, item, bounds, children, aContext, aRecorder);