--- a/content/events/src/nsEventStateManager.cpp
+++ b/content/events/src/nsEventStateManager.cpp
@@ -2909,17 +2909,19 @@ nsEventStateManager::PostHandleEvent(nsP
         if (msEvent->scrollFlags & nsMouseScrollEvent::kIsHorizontal) {
           mLastLineScrollConsumedX = (nsEventStatus_eConsumeNoDefault == *aStatus);
         } else if (msEvent->scrollFlags & nsMouseScrollEvent::kIsVertical) {
           mLastLineScrollConsumedY = (nsEventStatus_eConsumeNoDefault == *aStatus);
         }
         if (!(msEvent->scrollFlags & nsMouseScrollEvent::kHasPixels)) {
           // No generated pixel scroll event will follow.
           // Create and send a pixel scroll DOM event now.
+          nsWeakFrame weakFrame(aTargetFrame);
           SendPixelScrollEvent(aTargetFrame, msEvent, presContext, aStatus);
+          NS_ENSURE_STATE(weakFrame.IsAlive());
         }
       }
 
       if (*aStatus != nsEventStatus_eConsumeNoDefault) {
         // Build the preference keys, based on the event properties.
         NS_NAMED_LITERAL_CSTRING(actionslot,      ".action");
         NS_NAMED_LITERAL_CSTRING(sysnumlinesslot, ".sysnumlines");