diff --git a/src/vs/editor/common/modes/tokenizationRegistry.ts b/src/vs/editor/common/modes/tokenizationRegistry.ts
index 3d5d0097cb517c072a64f02fdfd1629e1da18d9d..fc3423047fb6fb37c46ae0b0b3f7e2292c39cc70 100644
--- a/src/vs/editor/common/modes/tokenizationRegistry.ts
+++ b/src/vs/editor/common/modes/tokenizationRegistry.ts
@@ -8,6 +8,7 @@ import { Emitter, Event } from 'vs/base/common/event';
 import { IDisposable, toDisposable } from 'vs/base/common/lifecycle';
 import { ColorId, ITokenizationRegistry, ITokenizationSupport, ITokenizationSupportChangedEvent } from 'vs/editor/common/modes';
 import { withUndefinedAsNull } from 'vs/base/common/types';
+import { keys } from 'vs/base/common/map';
 
 export class TokenizationRegistryImpl implements ITokenizationRegistry {
 
@@ -82,7 +83,7 @@ export class TokenizationRegistryImpl implements ITokenizationRegistry {
 	public setColorMap(colorMap: Color[]): void {
 		this._colorMap = colorMap;
 		this._onDidChange.fire({
-			changedLanguages: Array.from(this._map.keys()),
+			changedLanguages: keys(this._map),
 			changedColorMap: true
 		});
 	}