diff --git a/CHANGES.md b/CHANGES.md
index c1ed900509ed..91de0bdbf8c0 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -8,6 +8,8 @@ Change Log
 * Deprecated
   *
 * Improved KML NetworkLink compatibility by supporting the `Url` tag. [#3895](https://github.com/AnalyticalGraphicsInc/cesium/pull/3895).
+* Fixed exaggerated terrain tiles disappearing. [#3676](https://github.com/AnalyticalGraphicsInc/cesium/issues/3676)
+* Fixed infinite horizontal 2D scrolling in IE/Edge. [#3893](https://github.com/AnalyticalGraphicsInc/cesium/issues/3893)
 
 ### 1.21 - 2016-05-02
 
@@ -22,7 +24,6 @@ Change Log
 * Fixed issue causing the fog to go dark and the atmosphere to flicker when the camera clips the globe. [#3178](https://github.com/AnalyticalGraphicsInc/cesium/issues/3178)
 * Fixed a bug that caused an exception and rendering to stop when using `ArcGisMapServerImageryProvider` to connect to a MapServer specifying the Web Mercator projection and a fullExtent bigger than the valid extent of the projection. [#3854](https://github.com/AnalyticalGraphicsInc/cesium/pull/3854)
 * Fixed issue causing an exception when switching scene modes with an active KML network link. [#3865](https://github.com/AnalyticalGraphicsInc/cesium/issues/3865)
-* Fixed exaggerated terrain tiles disappearing. [#3676](https://github.com/AnalyticalGraphicsInc/cesium/issues/3676)
 
 ### 1.20 - 2016-04-01
 
diff --git a/Source/Scene/Scene.js b/Source/Scene/Scene.js
index 750f812da421..8796ce7de157 100644
--- a/Source/Scene/Scene.js
+++ b/Source/Scene/Scene.js
@@ -1763,37 +1763,40 @@ define([
         } else if (windowCoordinates.x > context.drawingBufferWidth * 0.5) {
             viewport.width = windowCoordinates.x;
 
+            var right = camera.frustum.right;
             camera.frustum.right = maxCoord.x - x;
 
             executeCommandsInViewport(true, scene, passState, backgroundColor, picking);
 
             viewport.x += windowCoordinates.x;
+            viewport.width = context.drawingBufferWidth - windowCoordinates.x;
 
             camera.position.x = -camera.position.x;
 
-            var right = camera.frustum.right;
-            camera.frustum.right = -camera.frustum.left;
-            camera.frustum.left = -right;
+            camera.frustum.left = -camera.frustum.right;
+            camera.frustum.right = camera.frustum.left + (right - camera.frustum.right);
 
             frameState.cullingVolume = camera.frustum.computeCullingVolume(camera.positionWC, camera.directionWC, camera.upWC);
             context.uniformState.update(frameState);
 
             executeCommandsInViewport(false, scene, passState, backgroundColor, picking);
         } else {
-            viewport.x += windowCoordinates.x;
-            viewport.width -= windowCoordinates.x;
+            viewport.x = windowCoordinates.x;
+            viewport.width = context.drawingBufferWidth - windowCoordinates.x;
 
+            var left = camera.frustum.left;
             camera.frustum.left = -maxCoord.x - x;
 
             executeCommandsInViewport(true, scene, passState, backgroundColor, picking);
 
-            viewport.x = viewport.x - viewport.width;
+            viewport.x = 0;
+            viewport.width = windowCoordinates.x;
 
             camera.position.x = -camera.position.x;
 
-            var left = camera.frustum.left;
-            camera.frustum.left = -camera.frustum.right;
-            camera.frustum.right = -left;
+            camera.frustum.right = -camera.frustum.left;
+            camera.frustum.left = camera.frustum.right + (left - camera.frustum.left);
+
 
             frameState.cullingVolume = camera.frustum.computeCullingVolume(camera.positionWC, camera.directionWC, camera.upWC);
             context.uniformState.update(frameState);