diff --git a/src/vs/code/electron-browser/sharedProcess/sharedProcessMain.ts b/src/vs/code/electron-browser/sharedProcess/sharedProcessMain.ts
index 964de555b25..ad96ee4aef7 100644
--- a/src/vs/code/electron-browser/sharedProcess/sharedProcessMain.ts
+++ b/src/vs/code/electron-browser/sharedProcess/sharedProcessMain.ts
@@ -209,13 +209,13 @@ class SharedProcessMain extends Disposable {
 		services.set(IExtensionRecommendationNotificationService, new ExtensionRecommendationNotificationServiceChannelClient(this.server.getChannel('extensionRecommendationNotification', activeWindowRouter)));
 
 		// Telemetry
-		const { appRoot, extensionsPath, extensionDevelopmentLocationURI, isBuilt, installSourcePath } = environmentService;
-
 		let telemetryService: ITelemetryService;
 		let telemetryAppender: ITelemetryAppender;
-		if (!extensionDevelopmentLocationURI && !environmentService.disableTelemetry && productService.enableTelemetry) {
+		if (!environmentService.isExtensionDevelopment && !environmentService.disableTelemetry && productService.enableTelemetry) {
 			telemetryAppender = new TelemetryLogAppender(loggerService, environmentService);
 
+			const { appRoot, extensionsPath, isBuilt, installSourcePath } = environmentService;
+
 			// Application Insights
 			if (productService.aiConfig && productService.aiConfig.asimovKey && isBuilt) {
 				const appInsightsAppender = new AppInsightsAppender('monacoworkbench', null, productService.aiConfig.asimovKey);
diff --git a/src/vs/code/node/cliProcessMain.ts b/src/vs/code/node/cliProcessMain.ts
index d50ab90f149..f330f43c192 100644
--- a/src/vs/code/node/cliProcessMain.ts
+++ b/src/vs/code/node/cliProcessMain.ts
@@ -135,8 +135,6 @@ class CliMain extends Disposable {
 		const stateService = new StateService(environmentService, logService);
 		services.set(IStateService, stateService);
 
-		const { appRoot, extensionsPath, extensionDevelopmentLocationURI, isBuilt, installSourcePath } = environmentService;
-
 		// Request
 		services.set(IRequestService, new SyncDescriptor(RequestService));
 
@@ -150,11 +148,13 @@ class CliMain extends Disposable {
 
 		// Telemetry
 		const appenders: AppInsightsAppender[] = [];
-		if (isBuilt && !extensionDevelopmentLocationURI && !environmentService.disableTelemetry && productService.enableTelemetry) {
+		if (environmentService.isBuilt && !environmentService.isExtensionDevelopment && !environmentService.disableTelemetry && productService.enableTelemetry) {
 			if (productService.aiConfig && productService.aiConfig.asimovKey) {
 				appenders.push(new AppInsightsAppender('monacoworkbench', null, productService.aiConfig.asimovKey));
 			}
 
+			const { appRoot, extensionsPath, installSourcePath } = environmentService;
+
 			const config: ITelemetryServiceConfig = {
 				appender: combinedAppender(...appenders),
 				sendErrorTelemetry: false,
diff --git a/src/vs/workbench/contrib/extensions/browser/extensionRecommendationsService.ts b/src/vs/workbench/contrib/extensions/browser/extensionRecommendationsService.ts
index 60fa348e8ae..5477d2147cf 100644
--- a/src/vs/workbench/contrib/extensions/browser/extensionRecommendationsService.ts
+++ b/src/vs/workbench/contrib/extensions/browser/extensionRecommendationsService.ts
@@ -105,7 +105,7 @@ export class ExtensionRecommendationsService extends Disposable implements IExte
 	}
 
 	private isEnabled(): boolean {
-		return this.galleryService.isEnabled() && !this.environmentService.extensionDevelopmentLocationURI;
+		return this.galleryService.isEnabled() && !this.environmentService.isExtensionDevelopment;
 	}
 
 	private async activateProactiveRecommendations(): Promise<void> {
diff --git a/src/vs/workbench/services/extensions/common/abstractExtensionService.ts b/src/vs/workbench/services/extensions/common/abstractExtensionService.ts
index fd1b5fd113b..a597c4f1a52 100644
--- a/src/vs/workbench/services/extensions/common/abstractExtensionService.ts
+++ b/src/vs/workbench/services/extensions/common/abstractExtensionService.ts
@@ -437,7 +437,7 @@ export abstract class AbstractExtensionService extends Disposable implements IEx
 	}
 
 	private async _handleExtensionTests(): Promise<void> {
-		if (!this._environmentService.extensionDevelopmentLocationURI || !this._environmentService.extensionTestsLocationURI) {
+		if (!this._environmentService.isExtensionDevelopment || !this._environmentService.extensionTestsLocationURI) {
 			return;
 		}
 
@@ -691,23 +691,8 @@ export abstract class AbstractExtensionService extends Disposable implements IEx
 		return extensions.filter(extension => this._isEnabled(extension));
 	}
 
-	private _isExtensionUnderDevelopment(extension: IExtensionDescription): boolean {
-		if (this._environmentService.isExtensionDevelopment) {
-			const extDevLocs = this._environmentService.extensionDevelopmentLocationURI;
-			if (extDevLocs) {
-				const extLocation = extension.extensionLocation;
-				for (let p of extDevLocs) {
-					if (isEqualOrParent(extLocation, p)) {
-						return true;
-					}
-				}
-			}
-		}
-		return false;
-	}
-
 	protected _isEnabled(extension: IExtensionDescription): boolean {
-		if (this._isExtensionUnderDevelopment(extension)) {
+		if (extension.isUnderDevelopment) {
 			// Never disable extensions under development
 			return true;
 		}
@@ -939,7 +924,7 @@ class ProposedApiController {
 
 		this.enableProposedApiForAll =
 			!_environmentService.isBuilt || // always allow proposed API when running out of sources
-			(!!_environmentService.extensionDevelopmentLocationURI && productService.quality !== 'stable') || // do not allow proposed API against stable builds when developing an extension
+			(_environmentService.isExtensionDevelopment && productService.quality !== 'stable') || // do not allow proposed API against stable builds when developing an extension
 			(this.enableProposedApiFor.length === 0 && Array.isArray(_environmentService.extensionEnabledProposedApi)); // always allow proposed API if --enable-proposed-api is provided without extension ID
 
 		this.productAllowProposedApi = new Set<string>();
diff --git a/src/vs/workbench/services/themes/browser/workbenchThemeService.ts b/src/vs/workbench/services/themes/browser/workbenchThemeService.ts
index 5611ff53613..90e4c55366c 100644
--- a/src/vs/workbench/services/themes/browser/workbenchThemeService.ts
+++ b/src/vs/workbench/services/themes/browser/workbenchThemeService.ts
@@ -692,19 +692,17 @@ export class WorkbenchThemeService implements IWorkbenchThemeService {
 
 class ThemeFileWatcher {
 
-	private inExtensionDevelopment: boolean;
 	private watchedLocation: URI | undefined;
 	private watcherDisposable: IDisposable | undefined;
 	private fileChangeListener: IDisposable | undefined;
 
-	constructor(private fileService: IFileService, environmentService: IWorkbenchEnvironmentService, private onUpdate: () => void) {
-		this.inExtensionDevelopment = !!environmentService.extensionDevelopmentLocationURI;
+	constructor(private fileService: IFileService, private environmentService: IWorkbenchEnvironmentService, private onUpdate: () => void) {
 	}
 
 	update(theme: { location?: URI, watch?: boolean; }) {
 		if (!resources.isEqual(theme.location, this.watchedLocation)) {
 			this.dispose();
-			if (theme.location && (theme.watch || this.inExtensionDevelopment)) {
+			if (theme.location && (theme.watch || this.environmentService.isExtensionDevelopment)) {
 				this.watchedLocation = theme.location;
 				this.watcherDisposable = this.fileService.watch(theme.location);
 				this.fileService.onDidFilesChange(e => {