diff --git a/Externals/winwebdiff b/Externals/winwebdiff
index a5c6478a5b5..ba7267eb68d 160000
--- a/Externals/winwebdiff
+++ b/Externals/winwebdiff
@@ -1 +1 @@
-Subproject commit a5c6478a5b5947d76cd8194545b5f1dac425f28e
+Subproject commit ba7267eb68df30d1acba34d64b80ad7d4827b67a
diff --git a/Src/MergeFrameCommon.cpp b/Src/MergeFrameCommon.cpp
index 700d6e0f5ce..7d1f5790036 100644
--- a/Src/MergeFrameCommon.cpp
+++ b/Src/MergeFrameCommon.cpp
@@ -88,7 +88,7 @@ void CMergeFrameCommon::RemoveBarBorder()
  */
 void CMergeFrameCommon::SetLastCompareResult(int nResult)
 {
-	HICON hReplace = (nResult == 0) ? m_hIdentical : m_hDifferent;
+	HICON hReplace = (nResult == 0) ? m_hIdentical : ((nResult < 0) ? nullptr : m_hDifferent);
 
 	if (m_hCurrent != hReplace)
 	{
diff --git a/Src/WebPageDiffFrm.cpp b/Src/WebPageDiffFrm.cpp
index 12314d955cd..c2653bad79e 100644
--- a/Src/WebPageDiffFrm.cpp
+++ b/Src/WebPageDiffFrm.cpp
@@ -323,6 +323,9 @@ void CWebPageDiffFrame::OnWebDiffEvent(const WebDiffEvent& event)
 {
 	switch (event.type)
 	{
+	case WebDiffEvent::NavigationStarting:
+		UpdateLastCompareResult();
+		break;
 	case WebDiffEvent::SourceChanged:
 	case WebDiffEvent::TabChanged:
 	{
@@ -877,7 +880,7 @@ int CWebPageDiffFrame::UpdateLastCompareResult()
 	int result = -1;
 	if (m_bCompareCompleted)
 	{
-		result = m_pWebDiffWindow->GetDiffCount() > 0 ? 1 : 0;
+		result = (m_pWebDiffWindow->GetCompareState() == IWebDiffWindow::COMPARED) ? (m_pWebDiffWindow->GetDiffCount() > 0 ? 1 : 0) : -1;
 		SetLastCompareResult(result);
 	}
 	return result;
diff --git a/Src/WinWebDiffLib.h b/Src/WinWebDiffLib.h
index 7cc74316652..d82da73dc05 100644
--- a/Src/WinWebDiffLib.h
+++ b/Src/WinWebDiffLib.h
@@ -6,7 +6,7 @@
 
 struct WebDiffEvent
 {
-	enum EVENT_TYPE { ZoomFactorChanged, NewWindowRequested, WindowCloseRequested, NavigationStarting, FrameNavigationStarting, HistoryChanged, SourceChanged, DocumentTitleChanged, NavigationCompleted, FrameNavigationCompleted, WebMessageReceived, FrameWebMessageReceived, TabChanged, HSCROLL, VSCROLL };
+	enum EVENT_TYPE { ZoomFactorChanged, NewWindowRequested, WindowCloseRequested, NavigationStarting, FrameNavigationStarting, HistoryChanged, SourceChanged, DocumentTitleChanged, NavigationCompleted, FrameNavigationCompleted, WebMessageReceived, FrameWebMessageReceived, TabChanged, HSCROLL, VSCROLL, CompareStateChanged };
 	EVENT_TYPE type;
 	int pane;
 };
@@ -62,6 +62,12 @@ struct IWebDiffWindow
 		EVENT_CLICK         = ( 1 << 1 ),
 		EVENT_INPUT         = ( 1 << 2 ),
 	};
+	enum CompareState
+	{
+		NOT_COMPARED,
+		COMPARING,
+		COMPARED,
+	};
 	struct DiffOptions
 	{
 		enum DiffAlgorithm {
@@ -183,6 +189,7 @@ struct IWebDiffWindow
 	virtual void SetSyncEventFlags(unsigned flags) = 0;
 	virtual bool GetSyncEventFlag(EventType event) const = 0;
 	virtual void SetSyncEventFlag(EventType event, bool flag) = 0;
+	virtual CompareState GetCompareState() const = 0;
 };
 
 extern "C"