diff --git a/OpenRa.Game/MainWindow.cs b/OpenRa.Game/MainWindow.cs
index b24aa9d02d..791583b63e 100644
--- a/OpenRa.Game/MainWindow.cs
+++ b/OpenRa.Game/MainWindow.cs
@@ -74,7 +74,7 @@ namespace OpenRa.Game
 			}
 		}
 
-		PointF scrollPos, oldPos;
+		PointF scrollPos;
 		int x1,y1;
 
 		protected override void OnMouseDown(MouseEventArgs e)
@@ -83,7 +83,6 @@ namespace OpenRa.Game
 
 			x1 = e.X;
 			y1 = e.Y;
-			oldPos = scrollPos;
 		}
 
 		protected override void OnMouseMove(MouseEventArgs e)
@@ -92,9 +91,14 @@ namespace OpenRa.Game
 
 			if (e.Button != 0)
 			{
-				scrollPos = oldPos;
 				scrollPos.X += x1 - e.X;
 				scrollPos.Y += y1 - e.Y;
+
+				x1 = e.X;
+				y1 = e.Y;
+
+				scrollPos.X = Util.Constrain( scrollPos.X, new Range<float>(0, map.Width * 24 - ClientSize.Width));
+				scrollPos.Y = Util.Constrain(scrollPos.Y, new Range<float>(0, map.Height * 24 - ClientSize.Height));
 			}
 		}
 
diff --git a/OpenRa.Game/Renderer.cs b/OpenRa.Game/Renderer.cs
index 1fbf25b614..700208baea 100644
--- a/OpenRa.Game/Renderer.cs
+++ b/OpenRa.Game/Renderer.cs
@@ -43,7 +43,7 @@ namespace OpenRa.Game
 		public void BeginFrame( PointF r1, PointF r2, PointF scroll )
 		{
 			device.Begin();
-			device.Clear(0, Surfaces.Color);
+			//device.Clear(0, Surfaces.Color);
 
 			shader.SetValue(scrollHandle, scroll);
 			shader.SetValue(r1Handle, r1);
diff --git a/OpenRa.Game/Util.cs b/OpenRa.Game/Util.cs
index 1bf5a6292c..2696780c8f 100644
--- a/OpenRa.Game/Util.cs
+++ b/OpenRa.Game/Util.cs
@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Text;
 using OpenRa.FileFormats;
 using System.Drawing;
+using BluntDirectX.Direct3D;
 
 namespace OpenRa.Game
 {
@@ -24,6 +25,11 @@ namespace OpenRa.Game
 			return (v > 0) ? v1 : v0;
 		}
 
+		public static float Constrain(float x, Range<float> range)
+		{
+			return x < range.Start ? range.Start : x > range.End ? range.End : x;
+		}
+
 		static PointF EncodeVertexAttributes(TextureChannel channel, int paletteLine)
 		{
 			Converter<TextureChannel, float> channelEncoder = delegate(TextureChannel c)