diff --git a/src/WinIMergeLib/ImgMergeBuffer.hpp b/src/WinIMergeLib/ImgMergeBuffer.hpp
index fa2f0e7..2de3e6e 100644
--- a/src/WinIMergeLib/ImgMergeBuffer.hpp
+++ b/src/WinIMergeLib/ImgMergeBuffer.hpp
@@ -143,9 +143,7 @@ class CImgMergeBuffer : public CImgDiffBuffer
 			m_bRO[i] = false;
 	}
 
-	virtual ~CImgMergeBuffer()
-	{
-	}
+	virtual ~CImgMergeBuffer() = default;
 
 	bool NewImages(int nImages, int nPages, int width, int height)
 	{
@@ -320,6 +318,12 @@ class CImgMergeBuffer : public CImgDiffBuffer
 	{
 		if (pane < 0 || pane >= m_nImages || m_bRO[pane])
 			return false;
+		left = (std::max)(left, 0);
+		top = (std::max)(top, 0);
+		right = (std::min)(right, static_cast<int>(m_imgOrig32[pane].width()));
+		bottom = (std::min)(bottom, static_cast<int>(m_imgOrig32[pane].height()));
+		if (right <= left || bottom <= top)
+			return false;
 
 		Image *oldbitmap = new Image(m_imgOrig32[pane]);
 
@@ -471,8 +475,7 @@ class CImgMergeBuffer : public CImgDiffBuffer
 
 	virtual bool CloseImages() override
 	{
-		for (int i = 0; i < m_nImages; ++i)
-			m_undoRecords.clear();
+		m_undoRecords.clear();
 		return CImgDiffBuffer::CloseImages();
 	}
 
@@ -484,6 +487,14 @@ class CImgMergeBuffer : public CImgDiffBuffer
 		Image *oldbitmap = new Image(m_imgOrig32[pane]);
 		{
 			TemporaryTransformation tmp(*this);
+			int width = (std::max)(static_cast<int>(m_imgOrig32[pane].width()), x + static_cast<int>(image.width()));
+			int height = (std::max)(static_cast<int>(m_imgOrig32[pane].height()), y + static_cast<int>(image.height()));
+			if (width != static_cast<int>(m_imgOrig32[pane].width()) || height != static_cast<int>(m_imgOrig32[pane].height()))
+			{
+				Image tmpImage = m_imgOrig32[pane];
+				m_imgOrig32[pane].setSize(width, height);
+				PasteImageInternal(pane, 0, 0, tmpImage);
+			}
 			PasteImageInternal(pane, x, y, image);
 		}
 		Image *newbitmap = new Image(m_imgOrig32[pane]);
diff --git a/src/WinIMergeLib/ImgMergeWindow.hpp b/src/WinIMergeLib/ImgMergeWindow.hpp
index 593378e..b5efe5d 100644
--- a/src/WinIMergeLib/ImgMergeWindow.hpp
+++ b/src/WinIMergeLib/ImgMergeWindow.hpp
@@ -364,13 +364,17 @@ class CImgMergeWindow : public IImgMergeWindow
 
 	void SetCurrentPage(int pane, int page) override
 	{
+		CommitOverlappedImages();
 		m_buffer.SetCurrentPage(pane, page);
+		UpdateScrollBars();
 		Invalidate();
 	}
 
 	void SetCurrentPageAll(int page) override
 	{
+		CommitOverlappedImages();
 		m_buffer.SetCurrentPageAll(page);
+		UpdateScrollBars();
 		Invalidate();
 	}
 
@@ -650,18 +654,21 @@ class CImgMergeWindow : public IImgMergeWindow
 
 	void CopyDiff(int diffIndex, int srcPane, int dstPane) override
 	{
+		CommitOverlappedImages();
 		m_buffer.CopyDiff(diffIndex, srcPane, dstPane);
 		Invalidate();
 	}
 
 	void CopyDiffAll(int srcPane, int dstPane) override
 	{
+		CommitOverlappedImages();
 		m_buffer.CopyDiffAll(srcPane, dstPane);
 		Invalidate();
 	}
 
 	int CopyDiff3Way(int dstPane) override
 	{
+		CommitOverlappedImages();
 		int result = m_buffer.CopyDiff3Way(dstPane);
 		Invalidate();
 		return result;
@@ -759,6 +766,7 @@ class CImgMergeWindow : public IImgMergeWindow
 		int pane = GetActivePane();
 		if (pane < 0 || !m_imgWindow[pane].IsRectanlgeSelectionVisible())
 			return false;
+		CommitOverlappedImages();
 		Image image;
 		RECT rc = ConvertToRealRect(pane, m_imgWindow[pane].GetRectangleSelection(), false);
 		m_buffer.CopySubImage(pane, rc.left, rc.top, rc.right, rc.bottom, image);
@@ -778,6 +786,12 @@ class CImgMergeWindow : public IImgMergeWindow
 			return false;
 		RECT rc = ConvertToRealRect(pane, m_imgWindow[pane].GetRectangleSelection(), false);
 		Cancel();
+		rc.left = (std::max)(rc.left, 0L);
+		rc.top = (std::max)(rc.top, 0L);
+		rc.right = (std::min)(rc.right, static_cast<long>(m_buffer.GetImageWidth(pane)));
+		rc.bottom = (std::min)(rc.bottom, static_cast<long>(m_buffer.GetImageHeight(pane)));
+		if (rc.right <= rc.left || rc.bottom <= rc.top)
+			return false;
 		bool result = m_buffer.DeleteRectangle(pane, rc.left, rc.top, rc.right, rc.bottom);
 		if (result)
 			Invalidate();
@@ -794,9 +808,6 @@ class CImgMergeWindow : public IImgMergeWindow
 		fipImageEx image;
 		image.pasteFromClipboard();
 		image.convertTo32Bits();
-		int maxwidth  = (std::max)(m_buffer.GetImageWidth(pane), static_cast<int>(image.getWidth()));
-		int maxheight = (std::max)(m_buffer.GetImageHeight(pane), static_cast<int>(image.getHeight()));
-		m_buffer.Resize(pane, maxwidth, maxheight);
 		imgWindow.SetOverlappedImage(image);
 		imgWindow.Invalidate();
 		return true;
@@ -835,6 +846,7 @@ class CImgMergeWindow : public IImgMergeWindow
 			m_imgWindow[pane].DeleteRectangleSelection();
 			m_imgWindow[pane].DeleteOverlappedImage();
 		}
+		UpdateScrollBars();
 		Invalidate();
 		return true;
 	}
@@ -1707,6 +1719,12 @@ class CImgMergeWindow : public IImgMergeWindow
 		Invalidate();
 	}
 
+	void CommitOverlappedImages()
+	{
+		for (int pane = 0; pane < m_nImages; ++pane)
+			PasteAndDeleteOverlappedImage(pane);
+	}
+
 	void PasteAndDeleteOverlappedImage(int pane)
 	{
 		PasteOverlappedImage(pane);