diff --git a/mozilla/layout/base/nsPresShell.cpp b/mozilla/layout/base/nsPresShell.cpp
index 171e07f7431..c77267039b7 100644
--- a/mozilla/layout/base/nsPresShell.cpp
+++ b/mozilla/layout/base/nsPresShell.cpp
@@ -6218,12 +6218,14 @@ PresShell::HandleEventInternal(nsEvent* aEvent, nsIView *aView, PRUint32 aFlags,
         }
       }
 
-      //Continue with second dispatch to system event handlers
+      //Continue with second dispatch to system event handlers.
+      // Need to null check mCurrentEventContent and mCurrentEventFrame
+      // since the previous dispatch could have nuked them.
       if (mCurrentEventContent) {
         rv = mCurrentEventContent->HandleDOMEvent(mPresContext, aEvent, nsnull, 
                                            aFlags | NS_EVENT_FLAG_SYSTEM_EVENT, aStatus);
       }
-      else {
+      else if (mCurrentEventFrame) {
         nsIContent* targetContent;
         if (NS_OK == mCurrentEventFrame->GetContentForEvent(mPresContext, aEvent, &targetContent) && nsnull != targetContent) {
           rv = targetContent->HandleDOMEvent(mPresContext, aEvent, nsnull, 
diff --git a/mozilla/layout/html/base/src/nsPresShell.cpp b/mozilla/layout/html/base/src/nsPresShell.cpp
index 171e07f7431..c77267039b7 100644
--- a/mozilla/layout/html/base/src/nsPresShell.cpp
+++ b/mozilla/layout/html/base/src/nsPresShell.cpp
@@ -6218,12 +6218,14 @@ PresShell::HandleEventInternal(nsEvent* aEvent, nsIView *aView, PRUint32 aFlags,
         }
       }
 
-      //Continue with second dispatch to system event handlers
+      //Continue with second dispatch to system event handlers.
+      // Need to null check mCurrentEventContent and mCurrentEventFrame
+      // since the previous dispatch could have nuked them.
       if (mCurrentEventContent) {
         rv = mCurrentEventContent->HandleDOMEvent(mPresContext, aEvent, nsnull, 
                                            aFlags | NS_EVENT_FLAG_SYSTEM_EVENT, aStatus);
       }
-      else {
+      else if (mCurrentEventFrame) {
         nsIContent* targetContent;
         if (NS_OK == mCurrentEventFrame->GetContentForEvent(mPresContext, aEvent, &targetContent) && nsnull != targetContent) {
           rv = targetContent->HandleDOMEvent(mPresContext, aEvent, nsnull,