diff --git a/layout/generic/nsSubDocumentFrame.cpp b/layout/generic/nsSubDocumentFrame.cpp
index 12fb76c56d7e..613811ce4968 100644
--- a/layout/generic/nsSubDocumentFrame.cpp
+++ b/layout/generic/nsSubDocumentFrame.cpp
@@ -462,6 +462,9 @@ nsSubDocumentFrame::BuildDisplayList(nsDisplayListBuilder*   aBuilder,
       if (mPreviousCaret) {
         aBuilder->MarkFrameModifiedDuringBuilding(mPreviousCaret);
       }
+      if (aBuilder->GetCaretFrame()) {
+        aBuilder->MarkFrameModifiedDuringBuilding(aBuilder->GetCaretFrame());
+      }
     }
     mPreviousCaret = aBuilder->GetCaretFrame();
   }