diff --git a/src/vs/code/electron-browser/issue/issueReporterMain.ts b/src/vs/code/electron-browser/issue/issueReporterMain.ts
index c65686451de..3191cdc737a 100644
--- a/src/vs/code/electron-browser/issue/issueReporterMain.ts
+++ b/src/vs/code/electron-browser/issue/issueReporterMain.ts
@@ -37,7 +37,6 @@ import { ILogService, getLogLevel } from 'vs/platform/log/common/log';
 import { OcticonLabel } from 'vs/base/browser/ui/octiconLabel/octiconLabel';
 import { normalizeGitHubUrl } from 'vs/code/electron-browser/issue/issueReporterUtil';
 import { Button } from 'vs/base/browser/ui/button/button';
-import { withUndefinedAsNull } from 'vs/base/common/types';
 import { SystemInfo, isRemoteDiagnosticError } from 'vs/platform/diagnostics/common/diagnostics';
 import { SpdLogService } from 'vs/platform/log/node/spdlogService';
 import { ISharedProcessService } from 'vs/platform/ipc/electron-browser/sharedProcessService';
@@ -232,7 +231,7 @@ export class IssueReporter extends Disposable {
 
 		styleTag.innerHTML = content.join('\n');
 		document.head.appendChild(styleTag);
-		document.body.style.color = withUndefinedAsNull(styles.color);
+		document.body.style.color = styles.color || '';
 	}
 
 	private handleExtensionData(extensions: IssueReporterExtensionData[]) {
diff --git a/src/vs/editor/common/model/textModelTokens.ts b/src/vs/editor/common/model/textModelTokens.ts
index 03e1c4bd6b7..7749d45b6ad 100644
--- a/src/vs/editor/common/model/textModelTokens.ts
+++ b/src/vs/editor/common/model/textModelTokens.ts
@@ -197,14 +197,13 @@ export class TextModelTokenization extends Disposable {
 	private readonly _textModel: TextModel;
 	private readonly _tokenizationStateStore: TokenizationStateStore;
 	private _revalidateTokensTimeout: any;
-	private _tokenizationSupport: ITokenizationSupport | null;
+	private _tokenizationSupport: ITokenizationSupport | undefined;
 
 	constructor(textModel: TextModel) {
 		super();
 		this._textModel = textModel;
 		this._tokenizationStateStore = new TokenizationStateStore();
 		this._revalidateTokensTimeout = -1;
-		this._tokenizationSupport = null;
 
 		this._register(TokenizationRegistry.onDidChange((e) => {
 			const languageIdentifier = this._textModel.getLanguageIdentifier();
@@ -428,11 +427,11 @@ export class TextModelTokenization extends Disposable {
 	}
 }
 
-function initializeTokenization(textModel: TextModel): [ITokenizationSupport | null, IState | null] {
+function initializeTokenization(textModel: TextModel): [ITokenizationSupport | undefined, IState | null] {
 	const languageIdentifier = textModel.getLanguageIdentifier();
 	let tokenizationSupport = (
 		textModel.isTooLargeForTokenization()
-			? null
+			? undefined
 			: TokenizationRegistry.get(languageIdentifier.language)
 	);
 	let initialState: IState | null = null;
@@ -441,7 +440,7 @@ function initializeTokenization(textModel: TextModel): [ITokenizationSupport | n
 			initialState = tokenizationSupport.getInitialState();
 		} catch (e) {
 			onUnexpectedError(e);
-			tokenizationSupport = null;
+			tokenizationSupport = undefined;
 		}
 	}
 	return [tokenizationSupport, initialState];
diff --git a/src/vs/editor/common/modes.ts b/src/vs/editor/common/modes.ts
index ede4308bd87..70feadc2677 100644
--- a/src/vs/editor/common/modes.ts
+++ b/src/vs/editor/common/modes.ts
@@ -1568,9 +1568,9 @@ export interface ITokenizationRegistry {
 
 	/**
 	 * Get the tokenization support for a language.
-	 * Returns `null` if not found.
+	 * Returns `undefined` if not found.
 	 */
-	get(language: string): ITokenizationSupport | null;
+	get(language: string): ITokenizationSupport | undefined;
 
 	/**
 	 * Get the promise of a tokenization support for a language.
@@ -1583,9 +1583,9 @@ export interface ITokenizationRegistry {
 	 */
 	setColorMap(colorMap: Color[]): void;
 
-	getColorMap(): Color[] | null;
+	getColorMap(): Color[] | undefined;
 
-	getDefaultBackground(): Color | null;
+	getDefaultBackground(): Color | undefined;
 }
 
 /**
diff --git a/src/vs/editor/common/modes/tokenizationRegistry.ts b/src/vs/editor/common/modes/tokenizationRegistry.ts
index fc3423047fb..d1492e39107 100644
--- a/src/vs/editor/common/modes/tokenizationRegistry.ts
+++ b/src/vs/editor/common/modes/tokenizationRegistry.ts
@@ -7,7 +7,6 @@ import { Color } from 'vs/base/common/color';
 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 {
@@ -18,11 +17,7 @@ export class TokenizationRegistryImpl implements ITokenizationRegistry {
 	private readonly _onDidChange = new Emitter<ITokenizationSupportChangedEvent>();
 	public readonly onDidChange: Event<ITokenizationSupportChangedEvent> = this._onDidChange.event;
 
-	private _colorMap: Color[] | null;
-
-	constructor() {
-		this._colorMap = null;
-	}
+	private _colorMap: Color[] | undefined;
 
 	public fire(languages: string[]): void {
 		this._onDidChange.fire({
@@ -76,8 +71,8 @@ export class TokenizationRegistryImpl implements ITokenizationRegistry {
 		return null;
 	}
 
-	public get(language: string): ITokenizationSupport | null {
-		return withUndefinedAsNull(this._map.get(language));
+	public get(language: string): ITokenizationSupport | undefined {
+		return this._map.get(language);
 	}
 
 	public setColorMap(colorMap: Color[]): void {
@@ -88,14 +83,14 @@ export class TokenizationRegistryImpl implements ITokenizationRegistry {
 		});
 	}
 
-	public getColorMap(): Color[] | null {
+	public getColorMap(): Color[] | undefined {
 		return this._colorMap;
 	}
 
-	public getDefaultBackground(): Color | null {
+	public getDefaultBackground(): Color | undefined {
 		if (this._colorMap && this._colorMap.length > ColorId.DefaultBackground) {
 			return this._colorMap[ColorId.DefaultBackground];
 		}
-		return null;
+		return undefined;
 	}
 }