diff --git a/src/vs/workbench/api/node/extHostDiagnostics.ts b/src/vs/workbench/api/node/extHostDiagnostics.ts
index 791de4d587d..e88ae6266c9 100644
--- a/src/vs/workbench/api/node/extHostDiagnostics.ts
+++ b/src/vs/workbench/api/node/extHostDiagnostics.ts
@@ -8,9 +8,9 @@ import { IMarkerData, MarkerSeverity } from 'vs/platform/markers/common/markers'
 import { URI } from 'vs/base/common/uri';
 import * as vscode from 'vscode';
 import { MainContext, MainThreadDiagnosticsShape, ExtHostDiagnosticsShape, IMainContext } from './extHost.protocol';
-import { DiagnosticSeverity, Diagnostic } from './extHostTypes';
+import { DiagnosticSeverity } from './extHostTypes';
 import * as converter from './extHostTypeConverters';
-import { mergeSort, equals } from 'vs/base/common/arrays';
+import { mergeSort } from 'vs/base/common/arrays';
 import { Event, Emitter } from 'vs/base/common/event';
 import { keys } from 'vs/base/common/map';
 
@@ -61,13 +61,9 @@ export class DiagnosticCollection implements vscode.DiagnosticCollection {
 
 		this._checkDisposed();
 		let toSync: vscode.Uri[] = [];
-		let hasChanged = true;
 
 		if (first instanceof URI) {
 
-			// check if this has actually changed
-			hasChanged = hasChanged && !equals(diagnostics, this.get(first), Diagnostic.isEqual);
-
 			if (!diagnostics) {
 				// remove this entry
 				this.delete(first);
@@ -109,14 +105,6 @@ export class DiagnosticCollection implements vscode.DiagnosticCollection {
 		// send event for extensions
 		this._onDidChangeDiagnostics.fire(toSync);
 
-		// if nothing has changed then there is nothing else to do
-		// we have updated the diagnostics but we don't send a message
-		// to the renderer. tho we have still send an event for other
-		// extensions because the diagnostic might carry more information
-		// than known to us
-		if (!hasChanged) {
-			return;
-		}
 		// compute change and send to main side
 		const entries: [URI, IMarkerData[]][] = [];
 		for (let uri of toSync) {
diff --git a/src/vs/workbench/test/electron-browser/api/extHostDiagnostics.test.ts b/src/vs/workbench/test/electron-browser/api/extHostDiagnostics.test.ts
index de772e5d024..02419a4d34e 100644
--- a/src/vs/workbench/test/electron-browser/api/extHostDiagnostics.test.ts
+++ b/src/vs/workbench/test/electron-browser/api/extHostDiagnostics.test.ts
@@ -188,7 +188,7 @@ suite('ExtHostDiagnostics', () => {
 		lastEntries = undefined!;
 	});
 
-	test('don\'t send message when not making a change', function () {
+	test('do send message when not making a change', function () {
 
 		let changeCount = 0;
 		let eventCount = 0;
@@ -209,7 +209,7 @@ suite('ExtHostDiagnostics', () => {
 		assert.equal(eventCount, 1);
 
 		collection.set(uri, [diag]);
-		assert.equal(changeCount, 1);
+		assert.equal(changeCount, 2);
 		assert.equal(eventCount, 2);
 	});
 
@@ -418,10 +418,10 @@ suite('ExtHostDiagnostics', () => {
 		assert.equal(callCount, 1);
 
 		collection.set(URI.parse('test:me'), array);
-		assert.equal(callCount, 1); // equal array
+		assert.equal(callCount, 2); // equal array
 
 		array.push(diag2);
 		collection.set(URI.parse('test:me'), array);
-		assert.equal(callCount, 2); // same but un-equal array
+		assert.equal(callCount, 3); // same but un-equal array
 	});
 });