diff --git a/src/apps/sudoku/CenteredViewContainer.cpp b/src/apps/sudoku/CenteredViewContainer.cpp
new file mode 100644
index 0000000000..3ce38673f3
--- /dev/null
+++ b/src/apps/sudoku/CenteredViewContainer.cpp
@@ -0,0 +1,44 @@
+/*
+ * Copyright 2007, Michael Pfeiffer, laplace@users.sourceforge.net. All rights reserved.
+ * Distributed under the terms of the MIT License.
+ */
+#include "CenteredViewContainer.h"
+
+CenteredViewContainer::CenteredViewContainer(BView *target, BRect frame, const char* name, uint32 resizingMode)
+	: BView(frame, name, resizingMode, B_WILL_DRAW | B_FRAME_EVENTS)
+	, fTarget(target)
+{
+	SetViewColor(B_TRANSPARENT_COLOR);
+		// to avoid flickering
+	AddChild(fTarget);
+	_CenterTarget(frame.Width(), frame.Height());
+}
+
+CenteredViewContainer::~CenteredViewContainer()
+{
+}
+
+void 
+CenteredViewContainer::Draw(BRect updateRect)
+{
+	FillRect(updateRect);
+}
+
+void 
+CenteredViewContainer::FrameResized(float width, float height)
+{
+	BView::FrameResized(width, height);
+	_CenterTarget(width, height);
+}
+
+void CenteredViewContainer::_CenterTarget(float width, float height)
+{
+	float size = width < height ? width : height;
+	float left = floor((width - size) / 2);
+	float top = floor((height - size) / 2);
+	fTarget->MoveTo(left, top);
+	fTarget->ResizeTo(size, size);
+	fTarget->FrameResized(size, size);
+		// in BeOS R5 BView::FrameResized is not (always) called automatically
+		// after ResizeTo() 
+}
diff --git a/src/apps/sudoku/CenteredViewContainer.h b/src/apps/sudoku/CenteredViewContainer.h
new file mode 100644
index 0000000000..a281a86c2e
--- /dev/null
+++ b/src/apps/sudoku/CenteredViewContainer.h
@@ -0,0 +1,27 @@
+/*
+ * Copyright 2007, Michael Pfeiffer, laplace@users.sourceforge.net. All rights reserved.
+ * Distributed under the terms of the MIT License.
+ */
+#ifndef CENTERED_VIEW_CONTAINER_H
+#define CENTERED_VIEW_CONTAINER_H
+
+
+#include <View.h>
+
+
+
+class CenteredViewContainer : public BView {
+public:
+	CenteredViewContainer(BView *target, BRect frame, const char* name, uint32 resizingMode);
+	virtual ~CenteredViewContainer();
+
+	void Draw(BRect updateRect);
+	void FrameResized(float width, float height);
+
+private:
+	void _CenterTarget(float width, float height);
+
+	BView *fTarget;
+};
+
+#endif // CENTERED_VIEW_CONTAINER_H
\ No newline at end of file
diff --git a/src/apps/sudoku/Jamfile b/src/apps/sudoku/Jamfile
index d216d3afc7..038f5384fc 100644
--- a/src/apps/sudoku/Jamfile
+++ b/src/apps/sudoku/Jamfile
@@ -3,6 +3,7 @@ SubDir HAIKU_TOP src apps sudoku ;
 SetSubDirSupportedPlatformsBeOSCompatible ;
 
 Application Sudoku :
+	CenteredViewContainer.cpp
 	ProgressWindow.cpp
 	Sudoku.cpp
 	SudokuField.cpp
diff --git a/src/apps/sudoku/SudokuGenerator.cpp b/src/apps/sudoku/SudokuGenerator.cpp
index 06d650a8d9..6ca45aa96b 100644
--- a/src/apps/sudoku/SudokuGenerator.cpp
+++ b/src/apps/sudoku/SudokuGenerator.cpp
@@ -10,6 +10,7 @@
 #include "SudokuField.h"
 #include "SudokuSolver.h"
 
+#include <stdio.h>
 
 SudokuGenerator::SudokuGenerator()
 {
diff --git a/src/apps/sudoku/SudokuView.cpp b/src/apps/sudoku/SudokuView.cpp
index 61cf1fdd47..85fded11cc 100644
--- a/src/apps/sudoku/SudokuView.cpp
+++ b/src/apps/sudoku/SudokuView.cpp
@@ -55,8 +55,11 @@ SudokuView::SudokuView(BRect frame, const char* name,
 	if (settings.FindBool("show cursor", &fShowCursor) != B_OK)
 		fShowCursor = false;
 
-	SetViewColor(255, 255, 240);
-	SetLowColor(ViewColor());
+	SetViewColor(B_TRANSPARENT_COLOR);
+		// to avoid flickering
+	rgb_color color = { 255, 255, 240 };
+	fBackgroundColor = color;
+	SetLowColor(color);
 	FrameResized(0, 0);
 }
 
@@ -99,7 +102,7 @@ SudokuView::_FilterString(const char* data, size_t dataLength, char* buffer,
 			continue;
 
 		if (!_ValidCharacter(data[i])) {
-			return B_BAD_DATA;
+			return B_BAD_VALUE;
 		}
 
 		buffer[out++] = data[i];
@@ -737,6 +740,11 @@ SudokuView::_DrawHints(uint32 x, uint32 y)
 void
 SudokuView::Draw(BRect /*updateRect*/)
 {
+	// draw one pixel border otherwise not covered
+	// by lines and fields
+	SetLowColor(fBackgroundColor);
+	StrokeRect(Bounds(), B_SOLID_LOW);
+
 	// draw lines
 
 	uint32 size = fField->Size();
@@ -778,9 +786,11 @@ SudokuView::Draw(BRect /*updateRect*/)
 				//SetLowColor(tint_color(ViewColor(), B_DARKEN_1_TINT));
 				SetLowColor(255, 255, 210);
 				FillRect(_Frame(x, y), B_SOLID_LOW);
-			} else
-				SetLowColor(ViewColor());
-
+			} else {
+				SetLowColor(fBackgroundColor);
+				FillRect(_Frame(x, y), B_SOLID_LOW);
+			}
+			
 			if (fShowKeyboardFocus && x == fKeyboardX && y == fKeyboardY)
 				_DrawKeyboardFocus();
 
diff --git a/src/apps/sudoku/SudokuView.h b/src/apps/sudoku/SudokuView.h
index f384ace9d9..4ccb7d1afe 100644
--- a/src/apps/sudoku/SudokuView.h
+++ b/src/apps/sudoku/SudokuView.h
@@ -75,6 +75,7 @@ private:
 	void _DrawKeyboardFocus();
 	void _DrawHints(uint32 x, uint32 y);
 
+	rgb_color		fBackgroundColor;
 	SudokuField*	fField;
 	uint32			fBlockSize;
 	float			fWidth, fHeight, fBaseline;
diff --git a/src/apps/sudoku/SudokuWindow.cpp b/src/apps/sudoku/SudokuWindow.cpp
index 559acaea33..e3d8721b66 100644
--- a/src/apps/sudoku/SudokuWindow.cpp
+++ b/src/apps/sudoku/SudokuWindow.cpp
@@ -6,6 +6,7 @@
 
 #include "SudokuWindow.h"
 
+#include "CenteredViewContainer.h"
 #include "ProgressWindow.h"
 #include "Sudoku.h"
 #include "SudokuField.h"
@@ -156,9 +157,13 @@ SudokuWindow::SudokuWindow()
 	top->SetViewColor(ui_color(B_PANEL_BACKGROUND_COLOR));
 	AddChild(top);
 
-	fSudokuView = new SudokuView(top->Bounds().InsetByCopy(10, 10),
-		"sudoku view", settings, B_FOLLOW_ALL);
-	top->AddChild(fSudokuView);
+	fSudokuView = new SudokuView(top->Bounds().InsetByCopy(10, 10).OffsetToSelf(0, 0),
+		"sudoku view", settings, B_FOLLOW_NONE);
+	CenteredViewContainer * container = new CenteredViewContainer(fSudokuView, 
+		top->Bounds().InsetByCopy(10, 10), 
+		"center", B_FOLLOW_ALL);
+	container->SetHighColor(top->ViewColor());
+	top->AddChild(container);
 
 	// add menu