diff --git a/extensions/css/client/src/colorDecorators.ts b/extensions/css/client/src/colorDecorators.ts
index 959b44565e1..cca08522d69 100644
--- a/extensions/css/client/src/colorDecorators.ts
+++ b/extensions/css/client/src/colorDecorators.ts
@@ -5,6 +5,7 @@
 'use strict';
 
 import { window, workspace, DecorationOptions, DecorationRenderOptions, Disposable, Range, TextDocument, TextEditor } from 'vscode';
+import { isEmbeddedContentUri, getHostDocumentUri } from './embeddedContentUri';
 
 const MAX_DECORATORS = 500;
 
@@ -49,51 +50,47 @@ export function activateColorDecorations(decoratorProvider: (uri: string) => The
 	workspace.onDidOpenTextDocument(triggerUpdateDecorations, null, disposables);
 	workspace.onDidCloseTextDocument(triggerUpdateDecorations, null, disposables);
 
+	workspace.textDocuments.forEach(triggerUpdateDecorations);
+
 	function triggerUpdateDecorations(document: TextDocument) {
 		let triggerUpdate = supportedLanguages[document.languageId];
-		let uri = document.uri.toString();
-		let timeout = pendingUpdateRequests[uri];
+		let documentUri = document.uri;
+		let documentUriStr = documentUri.toString();
+		let timeout = pendingUpdateRequests[documentUriStr];
 		if (typeof timeout !== 'undefined') {
 			clearTimeout(timeout);
 			triggerUpdate = true; // force update, even if languageId is not supported (anymore)
 		}
 		if (triggerUpdate) {
-			pendingUpdateRequests[uri] = setTimeout(() => {
-				updateDecorations(uri);
-				delete pendingUpdateRequests[uri];
+			pendingUpdateRequests[documentUriStr] = setTimeout(() => {
+				// check if the document is in use by an active editor
+				let contentHostUri = isEmbeddedContentUri(documentUri) ? getHostDocumentUri(documentUri) : documentUriStr;
+				window.visibleTextEditors.forEach(editor => {
+					if (editor.document && contentHostUri === editor.document.uri.toString()) {
+						updateDecorationForEditor(editor, documentUriStr);
+					}
+				});
+				delete pendingUpdateRequests[documentUriStr];
 			}, 500);
 		}
 	}
 
-	function updateDecorations(uri: string) {
-		window.visibleTextEditors.forEach(editor => {
-			let document = editor.document;
-			if (document && document.uri.toString() === uri) {
-				updateDecorationForEditor(editor);
-			}
-		});
-	}
-
-	function updateDecorationForEditor(editor: TextEditor) {
+	function updateDecorationForEditor(editor: TextEditor, contentUri: string) {
 		let document = editor.document;
-		if (supportedLanguages[document.languageId]) {
-			decoratorProvider(document.uri.toString()).then(ranges => {
-				let decorations = ranges.slice(0, MAX_DECORATORS).map(range => {
-					let color = document.getText(range);
-					return <DecorationOptions>{
-						range: range,
-						renderOptions: {
-							before: {
-								backgroundColor: color
-							}
+		decoratorProvider(contentUri).then(ranges => {
+			let decorations = ranges.slice(0, MAX_DECORATORS).map(range => {
+				let color = document.getText(range);
+				return <DecorationOptions>{
+					range: range,
+					renderOptions: {
+						before: {
+							backgroundColor: color
 						}
-					};
-				});
-				editor.setDecorations(colorsDecorationType, decorations);
+					}
+				};
 			});
-		} else {
-			editor.setDecorations(colorsDecorationType, []);
-		}
+			editor.setDecorations(colorsDecorationType, decorations);
+		});
 	}
 
 	return Disposable.from(...disposables);
diff --git a/extensions/css/client/src/embeddedContentUri.ts b/extensions/css/client/src/embeddedContentUri.ts
new file mode 100644
index 00000000000..8fccadaf83e
--- /dev/null
+++ b/extensions/css/client/src/embeddedContentUri.ts
@@ -0,0 +1,27 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+'use strict';
+
+import { Uri } from 'vscode';
+
+export const EMBEDDED_CONTENT_SCHEME = 'embedded-content';
+
+export function isEmbeddedContentUri(virtualDocumentUri: Uri): boolean {
+	return virtualDocumentUri.scheme === EMBEDDED_CONTENT_SCHEME;
+}
+
+export function getEmbeddedContentUri(parentDocumentUri: string, embeddedLanguageId: string): Uri {
+	return Uri.parse(EMBEDDED_CONTENT_SCHEME + '://' + embeddedLanguageId + '/' + encodeURIComponent(parentDocumentUri) + '.' + embeddedLanguageId);
+};
+
+export function getHostDocumentUri(virtualDocumentUri: Uri): string {
+	let languageId = virtualDocumentUri.authority;
+	let path = virtualDocumentUri.path.substring(1, virtualDocumentUri.path.length - languageId.length - 1); // remove leading '/' and new file extension
+	return decodeURIComponent(path);
+};
+
+export function getEmbeddedLanguageId(virtualDocumentUri: Uri): string {
+	return virtualDocumentUri.authority;
+}
\ No newline at end of file
diff --git a/extensions/css/server/src/cssServerMain.ts b/extensions/css/server/src/cssServerMain.ts
index 275a40750d4..14b17a4f9cf 100644
--- a/extensions/css/server/src/cssServerMain.ts
+++ b/extensions/css/server/src/cssServerMain.ts
@@ -176,8 +176,11 @@ connection.onCodeAction(codeActionParams => {
 
 connection.onRequest(ColorSymbolRequest.type, uri => {
 	let document = documents.get(uri);
-	let stylesheet = stylesheets.get(document);
-	return getLanguageService(document).findColorSymbols(document, stylesheet);
+	if (document) {
+		let stylesheet = stylesheets.get(document);
+		return getLanguageService(document).findColorSymbols(document, stylesheet);
+	}
+	return [];
 });
 
 connection.onRenameRequest(renameParameters => {