diff --git a/src/vs/platform/extensionManagement/common/extensionEnablementService.ts b/src/vs/platform/extensionManagement/common/extensionEnablementService.ts
index daf9f105b2290afc4e29b19175f80e5073eb6540..521c8af70a569e6bf0c2a41b3da198097e9969ec 100644
--- a/src/vs/platform/extensionManagement/common/extensionEnablementService.ts
+++ b/src/vs/platform/extensionManagement/common/extensionEnablementService.ts
@@ -56,25 +56,19 @@ export class ExtensionEnablementService implements IExtensionEnablementService {
 			return TPromise.wrap(false);
 		}
 
-		if (this.isDisabled(identifier) === !enable) {
-			return TPromise.wrap(false);
-		}
-
 		if (enable) {
 			if (workspace) {
-				this.enableExtension(identifier, StorageScope.WORKSPACE);
+				return this.enableExtension(identifier, StorageScope.WORKSPACE);
 			} else {
-				this.enableExtension(identifier, StorageScope.GLOBAL);
+				return this.enableExtension(identifier, StorageScope.GLOBAL);
 			}
 		} else {
 			if (workspace) {
-				this.disableExtension(identifier, StorageScope.WORKSPACE);
+				return this.disableExtension(identifier, StorageScope.WORKSPACE);
 			} else {
-				this.disableExtension(identifier, StorageScope.GLOBAL);
+				return this.disableExtension(identifier, StorageScope.GLOBAL);
 			}
 		}
-
-		return TPromise.wrap(true);
 	}
 
 	private getDisabledExtensions(): string[] {
@@ -99,9 +93,13 @@ export class ExtensionEnablementService implements IExtensionEnablementService {
 
 	private disableExtension(identifier: string, scope: StorageScope): TPromise<boolean> {
 		let disabledExtensions = this._getDisabledExtensions(scope);
-		disabledExtensions.push(identifier);
-		this._setDisabledExtensions(disabledExtensions, scope, identifier);
-		return TPromise.wrap(true);
+		const index = disabledExtensions.indexOf(identifier);
+		if (index === -1) {
+			disabledExtensions.push(identifier);
+			this._setDisabledExtensions(disabledExtensions, scope, identifier);
+			return TPromise.wrap(true);
+		}
+		return TPromise.wrap(false);
 	}
 
 	private enableExtension(identifier: string, scope: StorageScope): TPromise<boolean> {
@@ -110,8 +108,9 @@ export class ExtensionEnablementService implements IExtensionEnablementService {
 		if (index !== -1) {
 			disabledExtensions.splice(index, 1);
 			this._setDisabledExtensions(disabledExtensions, scope, identifier);
+			return TPromise.wrap(true);
 		}
-		return TPromise.wrap(true);
+		return TPromise.wrap(false);
 	}
 
 	private _getDisabledExtensions(scope: StorageScope): string[] {
diff --git a/src/vs/workbench/parts/extensions/node/extensionsWorkbenchService.ts b/src/vs/workbench/parts/extensions/node/extensionsWorkbenchService.ts
index 8c52a1b63949ea8b7431b04522e1bbc3010bac1a..e47c20280a59e91d3705f53f92e4d8990acd8dfc 100644
--- a/src/vs/workbench/parts/extensions/node/extensionsWorkbenchService.ts
+++ b/src/vs/workbench/parts/extensions/node/extensionsWorkbenchService.ts
@@ -502,7 +502,7 @@ export class ExtensionsWorkbenchService implements IExtensionsWorkbenchService {
 			return TPromise.wrap(null);
 		}
 
-		return this.extensionEnablementService.setEnablement(extension.identifier, enable, workspace).then(reload => {
+		return this.doSetEnablement(extension, enable, workspace).then(reload => {
 			this.telemetryService.publicLog(enable ? 'extension:enable' : 'extension:disable', extension.telemetryData);
 		});
 	}
@@ -520,6 +520,20 @@ export class ExtensionsWorkbenchService implements IExtensionsWorkbenchService {
 		}
 
 		return this.extensionService.uninstall(local);
+
+	}
+
+	private doSetEnablement(extension: IExtension, enable: boolean, workspace: boolean): TPromise<boolean> {
+		if (workspace) {
+			return this.extensionEnablementService.setEnablement(extension.identifier, enable, workspace);
+		}
+
+		const globalElablement = this.extensionEnablementService.setEnablement(extension.identifier, enable, false);
+		if (enable && this.workspaceContextService.getWorkspace()) {
+			const workspaceEnablement = this.extensionEnablementService.setEnablement(extension.identifier, enable, true);
+			return TPromise.join([globalElablement, workspaceEnablement]).then(values => values[0] || values[1]);
+		}
+		return globalElablement;
 	}
 
 	private onInstallExtension(event: InstallExtensionEvent): void {
diff --git a/src/vs/workbench/parts/extensions/test/node/extensionsWorkbenchService.test.ts b/src/vs/workbench/parts/extensions/test/node/extensionsWorkbenchService.test.ts
index c964be9d1403972dad10747c617a99505c0e3bf4..d377b57bdfe5e7553c164b2a6c5689c78bec4f5f 100644
--- a/src/vs/workbench/parts/extensions/test/node/extensionsWorkbenchService.test.ts
+++ b/src/vs/workbench/parts/extensions/test/node/extensionsWorkbenchService.test.ts
@@ -748,6 +748,29 @@ suite('ExtensionsWorkbenchService Test', () => {
 		assert.ok(!actual.disabledGlobally);
 	});
 
+	test('test enable extension globally when extension is disabled for workspace', () => {
+		instantiationService.get(IExtensionEnablementService).setEnablement('pub.a', false, true);
+		instantiationService.stubPromise(IExtensionManagementService, 'getInstalled', [aLocalExtension('a')]);
+		testObject = instantiationService.createInstance(ExtensionsWorkbenchService);
+
+		testObject.setEnablement(testObject.local[0], true);
+		const actual = testObject.local[0];
+
+		assert.ok(!actual.disabledForWorkspace);
+		assert.ok(!actual.disabledGlobally);
+	});
+
+	test('test disable extension globally should not disable for workspace', () => {
+		instantiationService.stubPromise(IExtensionManagementService, 'getInstalled', [aLocalExtension('a')]);
+		testObject = instantiationService.createInstance(ExtensionsWorkbenchService);
+
+		testObject.setEnablement(testObject.local[0], false);
+		const actual = testObject.local[0];
+
+		assert.ok(!actual.disabledForWorkspace);
+		assert.ok(actual.disabledGlobally);
+	});
+
 	test('test disabled flags are not updated for system extensions', () => {
 		instantiationService.stubPromise(IExtensionManagementService, 'getInstalled', [aLocalExtension('a', {}, { type: LocalExtensionType.System })]);
 		testObject = instantiationService.createInstance(ExtensionsWorkbenchService);