Handle disabling of the default theme extension. Fixes #44510

src/vs/workbench/services/themes/electron-browser/colorThemeData.ts

@@ -210,6 +210,16 @@ export class ColorThemeData implements IColorTheme {
 		return themeData;
 	}
 
+	static createLoadedEmptyTheme(id: string, settingsId: string): ColorThemeData {
+		let themeData = new ColorThemeData();
+		themeData.id = id;
+		themeData.label = '';
+		themeData.settingsId = settingsId;
+		themeData.isLoaded = true;
+		themeData.themeTokenColors = [{ settings: {} }];
+		return themeData;
+	}
+
 	static fromStorageData(input: string): ColorThemeData {
 		try {
 			let data = JSON.parse(input);

src/vs/workbench/services/themes/electron-browser/colorThemeStore.ts

@@ -51,8 +51,8 @@ export class ColorThemeStore {
 
 	public get onDidChange(): Event<ColorThemeData[]> { return this.onDidChangeEmitter.event; }
 
-	constructor( @IExtensionService private extensionService: IExtensionService) {
-		this.extensionsColorThemes = [];
+	constructor( @IExtensionService private extensionService: IExtensionService, defaultTheme: ColorThemeData) {
+		this.extensionsColorThemes = [defaultTheme];
 		this.onDidChangeEmitter = new Emitter<ColorThemeData[]>();
 		this.initialize();
 	}
@@ -98,7 +98,11 @@ export class ColorThemeStore {
 				collector.warn(nls.localize('invalid.path.1', "Expected `contributes.{0}.path` ({1}) to be included inside extension's folder ({2}). This might make the extension non-portable.", themesExtPoint.name, normalizedAbsolutePath, extensionFolderPath));
 			}
 			let themeData = ColorThemeData.fromExtensionTheme(theme, normalizedAbsolutePath, extensionData);
-			this.extensionsColorThemes.push(themeData);
+			if (themeData.id === this.extensionsColorThemes[0].id) {
+				this.extensionsColorThemes[0] = themeData;
+			} else {
+				this.extensionsColorThemes.push(themeData);
+			}
 		});
 	}
 

src/vs/workbench/services/themes/electron-browser/workbenchThemeService.ts

@@ -102,7 +102,7 @@ export class WorkbenchThemeService implements IWorkbenchThemeService {
 		@IInstantiationService private instantiationService: IInstantiationService) {
 
 		this.container = container;
-		this.colorThemeStore = new ColorThemeStore(extensionService);
+		this.colorThemeStore = new ColorThemeStore(extensionService, ColorThemeData.createLoadedEmptyTheme(DEFAULT_THEME_ID, DEFAULT_THEME_SETTING_VALUE));
 		this.onFileIconThemeChange = new Emitter<IFileIconTheme>();
 		this.iconThemeStore = new FileIconThemeStore(extensionService);
 		this.onColorThemeChange = new Emitter<IColorTheme>();