--- a/editor/libeditor/HTMLEditRules.cpp
+++ b/editor/libeditor/HTMLEditRules.cpp
@@ -6856,62 +6856,62 @@ HTMLEditRules::ReturnInParagraph(Selecti
       // We split the parent after the br we've just inserted.
       pointToSplitParentDivOrP.Set(brNode);
       DebugOnly<bool> advanced = pointToSplitParentDivOrP.AdvanceOffset();
       NS_WARNING_ASSERTION(advanced,
         "Failed to advance offset after the new <br>");
     }
   }
   EditActionResult result(
-    SplitParagraph(aSelection, aParentDivOrP, brNode,
-                   *pointToSplitParentDivOrP.Container(),
-                   pointToSplitParentDivOrP.Offset()));
+    SplitParagraph(aSelection, aParentDivOrP, pointToSplitParentDivOrP.AsRaw(),
+                   brNode));
   result.MarkAsHandled();
   if (NS_WARN_IF(result.Failed())) {
     return result;
   }
   return result;
 }
 
 nsresult
 HTMLEditRules::SplitParagraph(Selection& aSelection,
-                              Element& aPara,
-                              nsIContent* aBRNode,
-                              nsINode& aSelNode,
-                              int32_t aOffset)
+                              Element& aParentDivOrP,
+                              const EditorRawDOMPoint& aStartOfRightNode,
+                              nsIContent* aNextBRNode)
 {
   if (NS_WARN_IF(!mHTMLEditor)) {
     return NS_ERROR_NOT_AVAILABLE;
   }
 
   RefPtr<HTMLEditor> htmlEditor = mHTMLEditor;
 
   // split para
   // get ws code to adjust any ws
   nsCOMPtr<nsIContent> leftPara, rightPara;
-  nsCOMPtr<nsINode> selNode = &aSelNode;
+  nsCOMPtr<nsINode> selNode = aStartOfRightNode.Container();
+  int32_t selOffset = aStartOfRightNode.Offset();
   nsresult rv =
     WSRunObject::PrepareToSplitAcrossBlocks(htmlEditor,
-                                            address_of(selNode), &aOffset);
+                                            address_of(selNode), &selOffset);
   // XXX When it fails, why do we need to return selection node?  (Why can the
   //     caller trust the result even when it returns error?)
   NS_ENSURE_SUCCESS(rv, rv);
   // split the paragraph
   NS_ENSURE_STATE(selNode->IsContent());
   int32_t offset =
-    htmlEditor->SplitNodeDeep(aPara, *selNode->AsContent(), aOffset,
+    htmlEditor->SplitNodeDeep(aParentDivOrP, *selNode->AsContent(), selOffset,
                               HTMLEditor::EmptyContainers::yes,
                               getter_AddRefs(leftPara),
                               getter_AddRefs(rightPara));
   if (NS_WARN_IF(offset == -1)) {
     return NS_ERROR_FAILURE;
   }
-  // get rid of the break, if it is visible (otherwise it may be needed to prevent an empty p)
-  if (aBRNode && htmlEditor->IsVisibleBRElement(aBRNode)) {
-    rv = htmlEditor->DeleteNode(aBRNode);
+  // Get rid of the break, if it is visible (otherwise it may be needed to
+  // prevent an empty p).
+  if (aNextBRNode && htmlEditor->IsVisibleBRElement(aNextBRNode)) {
+    rv = htmlEditor->DeleteNode(aNextBRNode);
     NS_ENSURE_SUCCESS(rv, rv);
   }
 
   // remove ID attribute on the paragraph we just created
   rv = htmlEditor->RemoveAttribute(rightPara->AsElement(), nsGkAtoms::id);
   NS_ENSURE_SUCCESS(rv, rv);
 
   // We need to ensure to both paragraphs visible even if they are empty.

--- a/editor/libeditor/HTMLEditRules.h
+++ b/editor/libeditor/HTMLEditRules.h
@@ -309,28 +309,30 @@ protected:
    *                        split the paragraph, marked as handled.
    */
   EditActionResult ReturnInParagraph(Selection& aSelection,
                                      Element& aParentDivOrP);
 
   /**
    * SplitParagraph() splits the parent block, aPara, at aSelNode - aOffset.
    *
-   * @param aSelection  The selection.
-   * @param aPara       The parent block to be split.
-   * @param aBRNode     Next <br> node if there is.  Otherwise, nullptr.
-   *                    If this is not nullptr, the <br> node may be removed.
-   * @param aSelNode    Set the selection container to split aPara at.
-   * @param aOffset     Set the offset in the container.
+   * @param aSelection          The selection.
+   * @param aParentDivOrP       The parent block to be split.  This must be <p>
+   *                            or <div> element.
+   * @param aStartOfRightNode   The point to be start of right node after
+   *                            split.  This must be descendant of
+   *                            aParentDivOrP.
+   * @param aNextBRNode         Next <br> node if there is.  Otherwise, nullptr.
+   *                            If this is not nullptr, the <br> node may be
+   *                            removed.
    */
   nsresult SplitParagraph(Selection& aSelection,
-                          Element& aPara,
-                          nsIContent* aBRNode,
-                          nsINode& aSelNode,
-                          int32_t aOffset);
+                          Element& aParentDivOrP,
+                          const EditorRawDOMPoint& aStartOfRightNode,
+                          nsIContent* aBRNode);
 
   nsresult ReturnInListItem(Selection& aSelection, Element& aHeader,
                             nsINode& aNode, int32_t aOffset);
   nsresult AfterEditInner(EditAction action,
                           nsIEditor::EDirection aDirection);
   nsresult RemovePartOfBlock(Element& aBlock, nsIContent& aStartChild,
                              nsIContent& aEndChild);
   void SplitBlock(Element& aBlock,