--- a/editor/libeditor/HTMLAnonymousNodeEditor.cpp
+++ b/editor/libeditor/HTMLAnonymousNodeEditor.cpp
@@ -171,16 +171,24 @@ HTMLEditor::CreateAnonymousElement(nsIAt
     return nullptr;
   }
 
   nsCOMPtr<nsIContent> parentContent = do_QueryInterface(aParentNode);
   if (NS_WARN_IF(!parentContent)) {
     return nullptr;
   }
 
+  // Don't put anonymous editor element into non-HTML element.
+  // It is mainly for avoiding other anonymous element being inserted
+  // into <svg:use>, but in general we probably don't want to insert
+  // some random HTML anonymous element into a non-HTML element.
+  if (!parentContent->IsHTMLElement()) {
+    return nullptr;
+  }
+
   nsCOMPtr<nsIDocument> doc = GetDocument();
   if (NS_WARN_IF(!doc)) {
     return nullptr;
   }
 
   // Get the pres shell
   nsCOMPtr<nsIPresShell> ps = GetPresShell();
   if (NS_WARN_IF(!ps)) {