diff --git a/extensions/git/src/dirtydiff.ts b/extensions/git/src/dirtydiff.ts
new file mode 100644
index 0000000000000000000000000000000000000000..62d4bef1d81be02909fafc7f1ea8af98764b7753
--- /dev/null
+++ b/extensions/git/src/dirtydiff.ts
@@ -0,0 +1,29 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+'use strict';
+
+import { Event, TextEditor, window } from 'vscode';
+import { IDisposable, dispose, mapEvent } from './util';
+
+type TextEditorsEvent = Event<TextEditor[]>;
+
+export class DirtyDiffDecorator implements IDisposable {
+
+	private disposables: IDisposable[] = [];
+
+	constructor() {
+		mapEvent(window.onDidChangeActiveTextEditor, () => window.visibleTextEditors)
+			(this.onDidVisibleEditorsChange, this, this.disposables);
+	}
+
+	private onDidVisibleEditorsChange(textEditors: TextEditor[]) {
+		// TODO
+	}
+
+	dispose(): void {
+		this.disposables = dispose(this.disposables);
+	}
+}
\ No newline at end of file
diff --git a/extensions/git/src/extension.ts b/extensions/git/src/extension.ts
index 7abb65c036eb4d9446f10a37e50c598fd84d0414..650bb4205af62a0e4ce0b76ecc3a8b7dcd293155 100644
--- a/extensions/git/src/extension.ts
+++ b/extensions/git/src/extension.ts
@@ -5,7 +5,15 @@
 
 'use strict';
 
-import * as vscode from 'vscode';
+import { ExtensionContext } from 'vscode';
+import { DirtyDiffDecorator } from './dirtydiff';
 
-export function activate(context: vscode.ExtensionContext) { }
-export function deactivate() { }
\ No newline at end of file
+export function activate(context: ExtensionContext) {
+	context.subscriptions.push(
+		new DirtyDiffDecorator()
+	);
+}
+
+export function deactivate() {
+
+}
\ No newline at end of file
diff --git a/extensions/git/src/util.ts b/extensions/git/src/util.ts
new file mode 100644
index 0000000000000000000000000000000000000000..d9ca2b757927b5817fccb3d4f79a5bbb59bc611d
--- /dev/null
+++ b/extensions/git/src/util.ts
@@ -0,0 +1,25 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+'use strict';
+
+import { Event } from 'vscode';
+
+export interface IDisposable {
+	dispose(): void;
+}
+
+export function dispose<T extends IDisposable>(disposables: T[]): T[] {
+	disposables.forEach(d => d.dispose());
+	return [];
+}
+
+export function mapEvent<I, O>(event: Event<I>, map: (i: I) => O): Event<O> {
+	return (listener, thisArgs = null, disposables?) => event(i => listener.call(thisArgs, map(i)), null, disposables);
+}
+
+export function filterEvent<T>(event: Event<T>, filter: (e: T) => boolean): Event<T> {
+	return (listener, thisArgs = null, disposables?) => event(e => filter(e) && listener.call(thisArgs, e), null, disposables);
+}
\ No newline at end of file
diff --git a/extensions/git/tsconfig.json b/extensions/git/tsconfig.json
index f72a72f83c7ce226176296e70537870607acb854..8cb1633437728038691588a558cc8917c812ade2 100644
--- a/extensions/git/tsconfig.json
+++ b/extensions/git/tsconfig.json
@@ -1,16 +1,11 @@
 {
 	"compilerOptions": {
+		"noLib": true,
+		"target": "es5",
 		"module": "commonjs",
-		"target": "es6",
-		"outDir": "out",
-		"lib": [
-			"es6"
-		],
-		"sourceMap": true,
-		"rootDir": "."
+		"outDir": "./out"
 	},
 	"exclude": [
-		"node_modules",
-		".vscode-test"
+		"node_modules"
 	]
 }
\ No newline at end of file