diff --git a/src/item-index.ts b/src/item-index.ts
index f2ef995a..216546a3 100644
--- a/src/item-index.ts
+++ b/src/item-index.ts
@@ -89,7 +89,7 @@ class ItemIndex extends LitElement {
     for (const item of this.items) {
       if (
         item.sourceUrl.indexOf(this.query) >= 0 ||
-        item.filename.indexOf(this.query) >= 0 ||
+        (item.filename && item.filename.indexOf(this.query) >= 0) ||
         Boolean(item.loadUrl && item.loadUrl.indexOf(this.query) >= 0) ||
         (item.title && item.title.indexOf(this.query) >= 0)
       ) {
diff --git a/webpack.config.js b/webpack.config.js
index 6fbeb1e8..21dcccfa 100644
--- a/webpack.config.js
+++ b/webpack.config.js
@@ -94,7 +94,7 @@ const electronPreloadConfig = (/*env, argv*/) => {
   return merge(tsConfig, config);
 };
 
-const browserConfig = (/*env, argv*/) => {
+const browserConfig = (env, argv) => {
   const isDevServer = process.env.WEBPACK_SERVE;
 
   /** @type {import('webpack').Configuration['entry']} */
@@ -125,7 +125,7 @@ const browserConfig = (/*env, argv*/) => {
     },
     entry,
     optimization,
-
+    devtool: argv.mode === "production" ? undefined : "source-map",
     output: {
       path: path.join(__dirname),
       filename: "[name].js",