diff --git a/packages/perspective-workspace/build.js b/packages/perspective-workspace/build.js
index a2f571a2c4..4b161d9ebf 100644
--- a/packages/perspective-workspace/build.js
+++ b/packages/perspective-workspace/build.js
@@ -29,7 +29,9 @@ const BUILD = [
             InlineCSSPlugin(),
             IgnoreCSSPlugin(),
             IgnoreFontsPlugin(),
-            NodeModulesExternal(),
+
+            // Inlining `lumino` and importing the `.ts` source saves _50kb_
+            NodeModulesExternal("@lumino"),
         ],
         loader: {
             ".html": "text",
diff --git a/tools/perspective-build/external.js b/tools/perspective-build/external.js
index f2946e384f..2ed8494544 100644
--- a/tools/perspective-build/external.js
+++ b/tools/perspective-build/external.js
@@ -1,11 +1,13 @@
-exports.NodeModulesExternal = function NodeModulesExternal() {
+exports.NodeModulesExternal = function NodeModulesExternal(whitelist) {
     function setup(build) {
         build.onResolve({filter: /^[A-Za-z0-9\@]/}, (args) => {
-            return {
-                path: args.path,
-                external: true,
-                namespace: "skip-node-modules",
-            };
+            if (!whitelist || !args.path.startsWith(whitelist)) {
+                return {
+                    path: args.path,
+                    external: true,
+                    namespace: "skip-node-modules",
+                };
+            }
         });
     }