diff --git a/packages/vscode/src/client.ts b/packages/vscode/src/client.ts
index fa31b7ea6..3266e6ed2 100644
--- a/packages/vscode/src/client.ts
+++ b/packages/vscode/src/client.ts
@@ -6,6 +6,7 @@ import "./fill/windowsService";
 import "./fill/environmentService";
 import "./fill/vscodeTextmate";
 import "./fill/codeEditor";
+import "./fill/mouseEvent";
 import { PasteAction } from "./fill/paste";
 import "./fill/dom";
 import "./vscode.scss";
diff --git a/packages/vscode/src/fill/mouseEvent.ts b/packages/vscode/src/fill/mouseEvent.ts
new file mode 100644
index 000000000..bfef104da
--- /dev/null
+++ b/packages/vscode/src/fill/mouseEvent.ts
@@ -0,0 +1,19 @@
+import * as mouse from "vs/base/browser/mouseEvent";
+
+/**
+ * Fix the wheel event for Firefox.
+ */
+class StandardWheelEvent extends mouse.StandardWheelEvent {
+
+	public constructor(event: mouse.IMouseWheelEvent | null) {
+		super(
+			event,
+			(-(event as any as MouseWheelEvent).deltaX || 0) / 3, // tslint:disable-line no-any
+			(-(event as any as MouseWheelEvent).deltaY || 0) / 3, // tslint:disable-line no-any
+		);
+	}
+
+}
+
+const target = mouse as typeof mouse;
+target.StandardWheelEvent = StandardWheelEvent;
diff --git a/scripts/vscode.patch b/scripts/vscode.patch
index 39360307b..51af9d26d 100644
--- a/scripts/vscode.patch
+++ b/scripts/vscode.patch
@@ -1,32 +1,3 @@
-diff --git a/src/vs/base/browser/mouseEvent.ts b/src/vs/base/browser/mouseEvent.ts
-index 89ff65ec49..bc0cf2b08c 100644
---- a/src/vs/base/browser/mouseEvent.ts
-+++ b/src/vs/base/browser/mouseEvent.ts
-@@ -147,12 +147,15 @@ export class StandardWheelEvent {
- 		if (e) {
- 			let e1 = <IWebKitMouseWheelEvent><any>e;
- 			let e2 = <IGeckoMouseWheelEvent><any>e;
-+			let e3 = <MouseWheelEvent><any>e;
- 
- 			// vertical delta scroll
- 			if (typeof e1.wheelDeltaY !== 'undefined') {
- 				this.deltaY = e1.wheelDeltaY / 120;
- 			} else if (typeof e2.VERTICAL_AXIS !== 'undefined' && e2.axis === e2.VERTICAL_AXIS) {
- 				this.deltaY = -e2.detail / 3;
-+			} else if (typeof e3.deltaY !== "undefined") {
-+				this.deltaY = -e3.deltaY / 3;
- 			}
- 
- 			// horizontal delta scroll
-@@ -164,6 +167,8 @@ export class StandardWheelEvent {
- 				}
- 			} else if (typeof e2.HORIZONTAL_AXIS !== 'undefined' && e2.axis === e2.HORIZONTAL_AXIS) {
- 				this.deltaX = -e.detail / 3;
-+			} else if (typeof e3.deltaX !== "undefined") {
-+				this.deltaX = -e3.deltaX / 3;
- 			}
- 
- 			// Assume a vertical scroll if nothing else worked
 diff --git a/src/vs/base/browser/ui/scrollbar/scrollableElement.ts b/src/vs/base/browser/ui/scrollbar/scrollableElement.ts
 index a6256deeba..69819e0f3a 100644
 --- a/src/vs/base/browser/ui/scrollbar/scrollableElement.ts