diff --git a/build/lib/extensions.js b/build/lib/extensions.js
index 73d2c7acef3cf7fbe356ad1d3f74af01a4680bd5..a98f3b890cf2b6cc5af9c202d2d4c2368f1955c0 100644
--- a/build/lib/extensions.js
+++ b/build/lib/extensions.js
@@ -29,12 +29,18 @@ const commit = util.getVersion(root);
 const sourceMappingURLBase = `https://ticino.blob.core.windows.net/sourcemaps/${commit}`;
 function fromLocal(extensionPath) {
     const webpackFilename = path.join(extensionPath, 'extension.webpack.config.js');
-    if (fs.existsSync(webpackFilename)) {
-        return fromLocalWebpack(extensionPath);
-    }
-    else {
-        return fromLocalNormal(extensionPath);
-    }
+    const input = fs.existsSync(webpackFilename)
+        ? fromLocalWebpack(extensionPath)
+        : fromLocalNormal(extensionPath);
+    const tmLanguageJsonFilter = filter('**/*.tmLanguage.json', { restore: true });
+    return input
+        .pipe(tmLanguageJsonFilter)
+        .pipe(buffer())
+        .pipe(es.mapSync((f) => {
+        f.contents = Buffer.from(JSON.stringify(JSON.parse(f.contents.toString('utf8'))));
+        return f;
+    }))
+        .pipe(tmLanguageJsonFilter.restore);
 }
 function fromLocalWebpack(extensionPath) {
     const result = es.through();
diff --git a/build/lib/extensions.ts b/build/lib/extensions.ts
index 4b185aff68171c3a339cf029c6ba52ed47392e5b..05bc70948468fbf6519a1664711f79a81ba488ec 100644
--- a/build/lib/extensions.ts
+++ b/build/lib/extensions.ts
@@ -30,11 +30,20 @@ const sourceMappingURLBase = `https://ticino.blob.core.windows.net/sourcemaps/${
 
 function fromLocal(extensionPath: string): Stream {
 	const webpackFilename = path.join(extensionPath, 'extension.webpack.config.js');
-	if (fs.existsSync(webpackFilename)) {
-		return fromLocalWebpack(extensionPath);
-	} else {
-		return fromLocalNormal(extensionPath);
-	}
+	const input = fs.existsSync(webpackFilename)
+		? fromLocalWebpack(extensionPath)
+		: fromLocalNormal(extensionPath);
+
+	const tmLanguageJsonFilter = filter('**/*.tmLanguage.json', { restore: true });
+
+	return input
+		.pipe(tmLanguageJsonFilter)
+		.pipe(buffer())
+		.pipe(es.mapSync((f: File) => {
+			f.contents = Buffer.from(JSON.stringify(JSON.parse(f.contents.toString('utf8'))));
+			return f;
+		}))
+		.pipe(tmLanguageJsonFilter.restore);
 }
 
 function fromLocalWebpack(extensionPath: string): Stream {