diff --git a/ImpressionistDoc.cpp b/ImpressionistDoc.cpp
index a3696af..c4ece37 100644
--- a/ImpressionistDoc.cpp
+++ b/ImpressionistDoc.cpp
@@ -254,6 +254,7 @@ int ImpressionistDoc::loadImageFromData(unsigned char* dataPtr, const int width,
 	}
 	delete[] m_ucPainting;
 	delete[] m_ucEdge;
+	delete[] m_ucBackup;
 	delete[] viewport.dataPtr;
 
 	m_ucBitmap = dataPtr;
@@ -265,9 +266,11 @@ int ImpressionistDoc::loadImageFromData(unsigned char* dataPtr, const int width,
 	m_ucPainting = new unsigned char[width*height * 3];
 	m_ucHistory = new unsigned char[width*height * 3];
 	m_ucEdge = new unsigned char[width*height * 3];
+	m_ucBackup = new unsigned char[width*height * 3];
 	memset(m_ucPainting, 0, width*height * 3);
 	memset(m_ucHistory, 0, width*height * 3);
 	memset(m_ucEdge, 0, width*height * 3);
+	memset(m_ucBackup, 0, width*height * 3);
 
 	m_pUI->m_mainWindow->resize(m_pUI->m_mainWindow->x(),
 		m_pUI->m_mainWindow->y(),
diff --git a/PaintView.cpp b/PaintView.cpp
index 0edec57..55ef163 100644
--- a/PaintView.cpp
+++ b/PaintView.cpp
@@ -60,8 +60,9 @@ void PaintView::updateViewport()
 	});
 
 	m_pPaintBitstart = m_pDoc->viewport.dataPtr + 3 * ((m_pDoc->m_nPaintWidth * startrow) + scrollpos.x);
-
 	RestoreContent();
+	m_pPaintBitstart = m_pDoc->m_ucPainting +
+		3 * ((m_pDoc->m_nPaintWidth * startrow) + scrollpos.x);
 }
 
 void PaintView::updatePainting()
@@ -117,10 +118,10 @@ void PaintView::draw()
 	drawWidth = min( m_nWindowWidth, m_pDoc->m_nPaintWidth );
 	drawHeight = min( m_nWindowHeight, m_pDoc->m_nPaintHeight );
 
-	// if (uc_backup)
-	// {
-	// 	memcpy(m_pDoc->m_ucPainting, uc_backup, drawWidth*drawHeight * 3);
-	// }
+	if (m_pDoc->m_ucBackup)
+	{
+		memcpy(m_pDoc->m_ucPainting, m_pDoc->m_ucBackup, drawWidth*drawHeight * 3);
+	}
 
 	startrow = m_pDoc->m_nPaintHeight - (scrollpos.y + drawHeight);
 	if ( startrow < 0 ) startrow = 0;
@@ -139,7 +140,7 @@ void PaintView::draw()
 	if ( m_pDoc->m_ucPainting && !isAnEvent) 
 	{
 		RestoreContent();
-		// updateViewport();
+		updateViewport();
 	}
 
 	bool willSave = false;
@@ -202,15 +203,6 @@ void PaintView::draw()
 		painterly();
 		willPainterly = false;
 		willSave = true;
-	} else
-	{
-		// for debugging purpose
-		// Point source(coord.x + m_nStartCol, m_nEndRow - coord.y);
-		// Point target(coord.x, m_nWindowHeight - coord.y);
-		// if(source.x>=0 && source.y>=0 && source.x <= m_nWindowWidth-1 && source.y <= m_nWindowHeight)
-		// {
-		// 	m_pDoc->m_pCurrentBrush->BrushMove(source, target);
-		// }
 	}
 
 
@@ -226,11 +218,9 @@ void PaintView::draw()
 	{
 		SaveCurrentContent();
 		glFlush();
-		delete[] uc_backup;
-		uc_backup = new unsigned char[drawWidth*drawHeight * 3];
-		memcpy(uc_backup, m_pDoc->m_ucPainting, drawWidth*drawHeight * 3);
-		// updateViewport();
+		memcpy(m_pDoc->m_ucBackup, m_pDoc->m_ucPainting, drawWidth*drawHeight * 3);
 	}
+	updateViewport();
 
 
 	VideoProcessor::continueWriteStream();
diff --git a/PaintView.h b/PaintView.h
index 24cc574..5244811 100644
--- a/PaintView.h
+++ b/PaintView.h
@@ -61,7 +61,6 @@ class PaintView : public Fl_Gl_Window
 	std::default_random_engine rng = std::default_random_engine(std::chrono::system_clock::now().time_since_epoch().count());
 	Point scrollpos{0, 0};
 	int startrow = 0;
-	unsigned char *uc_backup = NULL;
 
 	void updateViewport();
 	void updatePainting();