diff --git a/layout/generic/nsFrame.cpp b/layout/generic/nsFrame.cpp
index 90bc3e594e9..9b9889b9d14 100644
--- a/layout/generic/nsFrame.cpp
+++ b/layout/generic/nsFrame.cpp
@@ -4889,8 +4889,11 @@ nsIFrame::SchedulePaint(PaintType aType)
   if (!pres || (pres->Document() && pres->Document()->IsResourceDoc())) {
     return;
   }
-  
-  MOZ_ASSERT(pres->GetContainerWeak(), "SchedulePaint in a detached pres context");
+  if (!pres->GetContainerWeak()) {
+    NS_WARNING("Shouldn't call SchedulePaint in a detached pres context");
+    return;
+  }
+
   pres->PresShell()->ScheduleViewManagerFlush(aType == PAINT_DELAYED_COMPRESS ?
                                               nsIPresShell::PAINT_DELAYED_COMPRESS :
                                               nsIPresShell::PAINT_DEFAULT);