diff --git a/extensions/emmet/.vscode/settings.json b/extensions/emmet/.vscode/settings.json
new file mode 100644
index 00000000000..505e7e4e316
--- /dev/null
+++ b/extensions/emmet/.vscode/settings.json
@@ -0,0 +1,3 @@
+{
+    "emmet.excludeLanguages": []
+}
\ No newline at end of file
diff --git a/src/vs/workbench/api/node/extHost.api.impl.ts b/src/vs/workbench/api/node/extHost.api.impl.ts
index 1df16a4716f..43b01031087 100644
--- a/src/vs/workbench/api/node/extHost.api.impl.ts
+++ b/src/vs/workbench/api/node/extHost.api.impl.ts
@@ -80,7 +80,7 @@ export function createApiFactory(
 
 	// Addressable instances
 	const extHostHeapService = threadService.set(ExtHostContext.ExtHostHeapService, new ExtHostHeapService());
-	const extHostDocumentsAndEditors = threadService.set(ExtHostContext.ExtHostDocumentsAndEditors, new ExtHostDocumentsAndEditors(threadService));
+	const extHostDocumentsAndEditors = threadService.set(ExtHostContext.ExtHostDocumentsAndEditors, new ExtHostDocumentsAndEditors(threadService, extensionService));
 	const extHostDocuments = threadService.set(ExtHostContext.ExtHostDocuments, new ExtHostDocuments(threadService, extHostDocumentsAndEditors));
 	const extHostDocumentContentProviders = threadService.set(ExtHostContext.ExtHostDocumentContentProviders, new ExtHostDocumentContentProvider(threadService, extHostDocumentsAndEditors));
 	const extHostDocumentSaveParticipant = threadService.set(ExtHostContext.ExtHostDocumentSaveParticipant, new ExtHostDocumentSaveParticipant(extHostDocuments, threadService.get(MainContext.MainThreadWorkspace)));
diff --git a/src/vs/workbench/api/node/extHostDocumentsAndEditors.ts b/src/vs/workbench/api/node/extHostDocumentsAndEditors.ts
index da9cc09702c..8129a12b69a 100644
--- a/src/vs/workbench/api/node/extHostDocumentsAndEditors.ts
+++ b/src/vs/workbench/api/node/extHostDocumentsAndEditors.ts
@@ -8,9 +8,10 @@ import Event, { Emitter } from 'vs/base/common/event';
 import { dispose } from 'vs/base/common/lifecycle';
 import { MainContext, ExtHostDocumentsAndEditorsShape, IDocumentsAndEditorsDelta, IMainContext } from './extHost.protocol';
 import { ExtHostDocumentData } from './extHostDocumentData';
-import { ExtHostTextEditor } from './extHostTextEditor';
+import { ExtHostTextEditor, ExtHostTextEditor2 } from './extHostTextEditor';
 import * as assert from 'assert';
 import * as typeConverters from './extHostTypeConverters';
+import { ExtHostExtensionService } from 'vs/workbench/api/node/extHostExtensionService';
 
 export class ExtHostDocumentsAndEditors implements ExtHostDocumentsAndEditorsShape {
 
@@ -29,7 +30,8 @@ export class ExtHostDocumentsAndEditors implements ExtHostDocumentsAndEditorsSha
 	readonly onDidChangeActiveTextEditor: Event<ExtHostTextEditor> = this._onDidChangeActiveTextEditor.event;
 
 	constructor(
-		private readonly _mainContext: IMainContext
+		private readonly _mainContext: IMainContext,
+		private readonly _extHostExtensions?: ExtHostExtensionService
 	) {
 	}
 
@@ -79,7 +81,9 @@ export class ExtHostDocumentsAndEditors implements ExtHostDocumentsAndEditorsSha
 				assert.ok(!this._editors.has(data.id), `editor '${data.id}' already exists!`);
 
 				const documentData = this._documents.get(data.document.toString());
-				const editor = new ExtHostTextEditor(
+				const editor = new ExtHostTextEditor2(
+					this._extHostExtensions,
+					this._mainContext.get(MainContext.MainThreadTelemetry),
 					this._mainContext.get(MainContext.MainThreadEditors),
 					data.id,
 					documentData,
diff --git a/src/vs/workbench/api/node/extHostTextEditor.ts b/src/vs/workbench/api/node/extHostTextEditor.ts
index 763969acc96..a3e9c45edae 100644
--- a/src/vs/workbench/api/node/extHostTextEditor.ts
+++ b/src/vs/workbench/api/node/extHostTextEditor.ts
@@ -6,17 +6,19 @@
 
 
 import { ok } from 'vs/base/common/assert';
-import { readonly, illegalArgument } from 'vs/base/common/errors';
+import { readonly, illegalArgument, V8CallSite } from 'vs/base/common/errors';
 import { IdGenerator } from 'vs/base/common/idGenerator';
 import { TPromise } from 'vs/base/common/winjs.base';
 import { ExtHostDocumentData } from 'vs/workbench/api/node/extHostDocumentData';
 import { Selection, Range, Position, EndOfLine, TextEditorRevealType, TextEditorLineNumbersStyle, SnippetString } from './extHostTypes';
 import { ISingleEditOperation } from 'vs/editor/common/editorCommon';
 import * as TypeConverters from './extHostTypeConverters';
-import { MainThreadEditorsShape, IResolvedTextEditorConfiguration, ITextEditorConfigurationUpdate } from './extHost.protocol';
+import { MainThreadEditorsShape, MainThreadTelemetryShape, IResolvedTextEditorConfiguration, ITextEditorConfigurationUpdate } from './extHost.protocol';
 import * as vscode from 'vscode';
 import { TextEditorCursorStyle } from 'vs/editor/common/config/editorOptions';
 import { IRange } from 'vs/editor/common/core/range';
+import { containsCommandLink } from 'vs/base/common/htmlContent';
+import { ExtHostExtensionService } from 'vs/workbench/api/node/extHostExtensionService';
 
 export class TextEditorDecorationType implements vscode.TextEditorDecorationType {
 
@@ -550,6 +552,70 @@ export class ExtHostTextEditor implements vscode.TextEditor {
 	}
 }
 
+export class ExtHostTextEditor2 extends ExtHostTextEditor {
+
+	constructor(
+		private readonly _extHostExtensions: ExtHostExtensionService,
+		private readonly _mainThreadTelemetry: MainThreadTelemetryShape,
+		proxy: MainThreadEditorsShape,
+		id: string,
+		document: ExtHostDocumentData,
+		selections: Selection[],
+		options: IResolvedTextEditorConfiguration,
+		viewColumn: vscode.ViewColumn
+	) {
+		super(proxy, id, document, selections, options, viewColumn);
+	}
+
+	setDecorations(decorationType: vscode.TextEditorDecorationType, rangesOrOptions: Range[] | vscode.DecorationOptions[]): void {
+		// (1) find out if this decoration is important for us
+		let usesCommandLink = false;
+		outer: for (const rangeOrOption of rangesOrOptions) {
+			if (Range.isRange(rangeOrOption)) {
+				break;
+			}
+			if (typeof rangeOrOption.hoverMessage === 'string' && containsCommandLink(rangeOrOption.hoverMessage)) {
+				usesCommandLink = true;
+				break;
+			} else if (Array.isArray(rangeOrOption.hoverMessage)) {
+				for (const message of rangeOrOption.hoverMessage) {
+					if (typeof message === 'string' && containsCommandLink(message)) {
+						usesCommandLink = true;
+						break outer;
+					}
+				}
+			}
+		}
+		// (2) send event for important decorations
+		if (usesCommandLink) {
+			let tag = new Error();
+			this._extHostExtensions.getExtensionPathIndex().then(index => {
+				const oldHandler = (<any>Error).prepareStackTrace;
+				(<any>Error).prepareStackTrace = (error: Error, stackTrace: V8CallSite[]) => {
+					for (const call of stackTrace) {
+						const extension = index.findSubstr(call.getFileName());
+						if (extension) {
+							this._mainThreadTelemetry.$publicLog('usesCommandLink', {
+								extension: extension.id,
+								from: 'decoration',
+							});
+							return;
+						}
+					}
+				};
+				// it all happens here...
+				// tslint:disable-next-line:no-unused-expression
+				tag.stack;
+				(<any>Error).prepareStackTrace = oldHandler;
+			});
+		}
+
+		// (3) do it
+		super.setDecorations(decorationType, rangesOrOptions);
+	}
+}
+
+
 function warnOnError(promise: TPromise<any>): void {
 	promise.then(null, (err) => {
 		console.warn(err);