diff --git a/build/gulpfile.extensions.js b/build/gulpfile.extensions.js
index ce9afa3eae9..8d53a62c3a9 100644
--- a/build/gulpfile.extensions.js
+++ b/build/gulpfile.extensions.js
@@ -44,6 +44,8 @@ const tasks = compilations.map(function (tsconfigFile) {
 	const root = path.join('extensions', relativeDirname);
 	const srcBase = path.join(root, 'src');
 	const src = path.join(srcBase, '**');
+	const srcOpts = { cwd: path.dirname(__dirname), base: srcBase };
+
 	const out = path.join(root, 'out');
 	const baseUrl = getBaseUrl(out);
 
@@ -65,7 +67,7 @@ const tasks = compilations.map(function (tsconfigFile) {
 
 		const compilation = tsb.create(absolutePath, overrideOptions, false, err => reporter(err.toString()));
 
-		return function () {
+		const pipeline = function () {
 			const input = es.through();
 			const tsFilter = filter(['**/*.ts', '!**/lib/lib*.d.ts', '!**/node_modules/**'], { restore: true });
 			const output = input
@@ -95,15 +97,19 @@ const tasks = compilations.map(function (tsconfigFile) {
 
 			return es.duplex(input, output);
 		};
-	}
 
-	const srcOpts = { cwd: path.dirname(__dirname), base: srcBase };
+		// add src-stream for project files
+		pipeline.tsProjectSrc = () => {
+			return compilation.src(srcOpts);
+		};
+		return pipeline;
+	}
 
 	const cleanTask = task.define(`clean-extension-${name}`, util.rimraf(out));
 
 	const compileTask = task.define(`compile-extension:${name}`, task.series(cleanTask, () => {
 		const pipeline = createPipeline(false, true);
-		const input = gulp.src(src, srcOpts);
+		const input = pipeline.tsProjectSrc();
 
 		return input
 			.pipe(pipeline())
@@ -112,7 +118,7 @@ const tasks = compilations.map(function (tsconfigFile) {
 
 	const watchTask = task.define(`watch-extension:${name}`, task.series(cleanTask, () => {
 		const pipeline = createPipeline(false);
-		const input = gulp.src(src, srcOpts);
+		const input = pipeline.tsProjectSrc();
 		const watchInput = watcher(src, srcOpts);
 
 		return watchInput
@@ -122,7 +128,7 @@ const tasks = compilations.map(function (tsconfigFile) {
 
 	const compileBuildTask = task.define(`compile-build-extension-${name}`, task.series(cleanTask, () => {
 		const pipeline = createPipeline(true, true);
-		const input = gulp.src(src, srcOpts);
+		const input = pipeline.tsProjectSrc();
 
 		return input
 			.pipe(pipeline())
diff --git a/extensions/typescript-basics/test/colorize-fixtures/tsconfig.json b/extensions/typescript-basics/test/colorize-fixtures/tsconfig_off.json
similarity index 100%
rename from extensions/typescript-basics/test/colorize-fixtures/tsconfig.json
rename to extensions/typescript-basics/test/colorize-fixtures/tsconfig_off.json
diff --git a/extensions/typescript-basics/test/colorize-results/tsconfig_json.json b/extensions/typescript-basics/test/colorize-results/tsconfig_off_json.json
similarity index 100%
rename from extensions/typescript-basics/test/colorize-results/tsconfig_json.json
rename to extensions/typescript-basics/test/colorize-results/tsconfig_off_json.json
diff --git a/package.json b/package.json
index 1e1daccda9a..24ab0c80255 100644
--- a/package.json
+++ b/package.json
@@ -97,7 +97,7 @@
     "gulp-rename": "^1.2.0",
     "gulp-replace": "^0.5.4",
     "gulp-shell": "^0.6.5",
-    "gulp-tsb": "4.0.0",
+    "gulp-tsb": "4.0.1",
     "gulp-tslint": "^8.1.3",
     "gulp-untar": "^0.0.7",
     "gulp-vinyl-zip": "^2.1.2",
diff --git a/yarn.lock b/yarn.lock
index ab352df288e..b83fba04083 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -3697,10 +3697,10 @@ gulp-symdest@^1.1.1:
     queue "^3.1.0"
     vinyl-fs "^2.4.3"
 
-gulp-tsb@4.0.0:
-  version "4.0.0"
-  resolved "https://registry.yarnpkg.com/gulp-tsb/-/gulp-tsb-4.0.0.tgz#3e5a0d191cb070f1c936f70e8a41c54ce2e0b5a0"
-  integrity sha512-Y1csbJ0g2ihZr2aYv7O3VR/IwBzgcK3pCrga3yJ1ZWi3Tx3hAd51Lra74VnLxfekK7aZAxqw7Y9QOmxNs8LW8w==
+gulp-tsb@4.0.1:
+  version "4.0.1"
+  resolved "https://registry.yarnpkg.com/gulp-tsb/-/gulp-tsb-4.0.1.tgz#be2d8900d9227abf0e728a33139891e49b9e85d3"
+  integrity sha512-HHR5qMjj/NyFlYdY6AIql7bWosFAknNfeJumwdkPkNaw6GtHVoaK+hPmWgmyK9Otf9nqcETtI5KI2vIla6Vhdw==
   dependencies:
     ansi-colors "^1.0.1"
     fancy-log "^1.3.2"