4 files changed, 37 insertions, 21 deletions
diff --git a/sw/source/core/inc/txtfrm.hxx b/sw/source/core/inc/txtfrm.hxx
index eebbf7a65541..77b244042551 100644
--- a/sw/source/core/inc/txtfrm.hxx
+++ b/sw/source/core/inc/txtfrm.hxx
@@ -88,23 +88,7 @@ struct Extent
     }
 };
 
-struct MergedPara
-{
-    std::vector<Extent> const extents;
-    /// note: cannot be const currently to avoid UB because SwTextGuess::Guess
-    /// const_casts it and modifies it
-    OUString mergedText;
-    /// most paragraph properties are taken from the first non-empty node
-    SwTextNode const*const pParaPropsNode;
-    /// except break attributes, those are taken from the first node
-    SwTextNode *const pFirstNode;
-    MergedPara(std::vector<Extent>&& rExtents, OUString const& rText, SwTextNode const*const pProps, SwTextNode *const pFirst)
-        : extents(std::move(rExtents)), mergedText(rText), pParaPropsNode(pProps), pFirstNode(pFirst)
-    {
-        assert(pParaPropsNode);
-        assert(pFirstNode);
-    }
-};
+struct MergedPara;
 
 std::pair<SwTextNode*, sal_Int32> MapViewToModel(MergedPara const&, TextFrameIndex nIndex);
 TextFrameIndex MapModelToView(MergedPara const&, SwTextNode const* pNode, sal_Int32 nIndex);
@@ -917,7 +901,27 @@ public:
 
 namespace sw {
 
-struct MergedPara;
+struct MergedPara
+{
+    sw::WriterMultiListener listener;
+    std::vector<Extent> const extents;
+    /// note: cannot be const currently to avoid UB because SwTextGuess::Guess
+    /// const_casts it and modifies it
+    OUString mergedText;
+    /// most paragraph properties are taken from the first non-empty node
+    SwTextNode const*const pParaPropsNode;
+    /// except break attributes, those are taken from the first node
+    SwTextNode *const pFirstNode;
+    MergedPara(SwTextFrame & rFrame, std::vector<Extent>&& rExtents,
+            OUString const& rText,
+            SwTextNode const*const pProps, SwTextNode *const pFirst)
+        : listener(rFrame), extents(std::move(rExtents)), mergedText(rText)
+        , pParaPropsNode(pProps), pFirstNode(pFirst)
+    {
+        assert(pParaPropsNode);
+        assert(pFirstNode);
+    }
+};
 
 /// iterate SwTextAttr in potentially merged text frame
 class MergedAttrIterBase
diff --git a/sw/source/core/layout/ssfrm.cxx b/sw/source/core/layout/ssfrm.cxx
index a0b035ebaee7..b2fd7113c0b4 100644
--- a/sw/source/core/layout/ssfrm.cxx
+++ b/sw/source/core/layout/ssfrm.cxx
@@ -438,7 +438,10 @@ void SwTextFrame::RegisterToNode(SwTextNode & rNode)
 {
     assert(&rNode != GetRegisteredIn());
     m_pMergedPara = sw::CheckParaRedlineMerge(*this, rNode);
-    rNode.Add( this );
+    if (!m_pMergedPara)
+    {
+        rNode.Add(this);
+    }
 }
 
 void SwLayoutFrame::DestroyImpl()
diff --git a/sw/source/core/text/redlnitr.cxx b/sw/source/core/text/redlnitr.cxx
index 44fa965d8387..0640001dddb0 100644
--- a/sw/source/core/text/redlnitr.cxx
+++ b/sw/source/core/text/redlnitr.cxx
@@ -55,6 +55,7 @@ CheckParaRedlineMerge(SwTextFrame & rFrame, SwTextNode & rTextNode)
         return nullptr;
     }
     bool bHaveRedlines(false);
+    std::vector<SwTextNode *> nodes{ &rTextNode };
     std::vector<sw::Extent> extents;
     OUStringBuffer mergedText;
     SwTextNode const* pParaPropsNode(nullptr);
@@ -92,6 +93,7 @@ CheckParaRedlineMerge(SwTextFrame & rFrame, SwTextNode & rTextNode)
             }
             pNode = pEnd->nNode.GetNode().GetTextNode();
             assert(pNode);
+            nodes.push_back(pNode);
             pNode->SetRedlineMergeFlag(SwNode::Merge::NonFirst);
         }
         nLastEnd = pEnd->nContent.GetIndex();
@@ -115,8 +117,14 @@ CheckParaRedlineMerge(SwTextFrame & rFrame, SwTextNode & rTextNode)
         assert(!mergedText.isEmpty());
         pParaPropsNode = extents.begin()->pNode; // para props from first node that isn't empty
     }
-    return o3tl::make_unique<sw::MergedPara>(std::move(extents),
-            mergedText.makeStringAndClear(), pParaPropsNode, &rTextNode);
+    auto pRet(o3tl::make_unique<sw::MergedPara>(rFrame, std::move(extents),
+                mergedText.makeStringAndClear(), pParaPropsNode, &rTextNode));
+    for (SwTextNode * pTmp : nodes)
+    {
+        pRet->listener.StartListening(pTmp);
+    }
+    rFrame.EndListeningAll();
+    return pRet;
 }
 
 } // namespace sw
diff --git a/sw/source/core/text/txtfrm.cxx b/sw/source/core/text/txtfrm.cxx
index b1d27f0360e2..8e5a7f221a9e 100644
--- a/sw/source/core/text/txtfrm.cxx
+++ b/sw/source/core/text/txtfrm.cxx
@@ -581,6 +581,7 @@ SwTextFrame::SwTextFrame(SwTextNode * const pNode, SwFrame* pSib )
     , mnFootnoteLine( 0 )
     , mnHeightOfLastLine( 0 )
     , mnAdditionalFirstLineOffset( 0 )
+    // note: this may change this->pRegisteredIn to m_pMergedPara->listeners
     , m_pMergedPara(CheckParaRedlineMerge(*this, *pNode)) // ensure it is inited
     , mnOffset( 0 )
     , mnCacheIndex( USHRT_MAX )