@@ -13,21 +13,27 @@ export default class ReduxHandler extends Listenable {
   }
 
   /**
-   * Initialize the handler. Must be called before adding events.
+   * Initialize the handler and wait until Redux has its first real state.
+   * Callers do not need to await this unless they use Redux immediately.
+   * @returns {Promise<void>}
+   * @throws when the Redux readiness promise is unavailable.
    */
   initialize() {
-    if (!__scratchAddonsRedux.target || this.initialized) return;
-    this.initialized = true;
-    __scratchAddonsRedux.target.addEventListener("statechanged", ({ detail }) => {
-      const newEvent = new CustomEvent("statechanged", {
-        detail: {
-          action: detail.action,
-          prev: detail.prev,
-          next: detail.next,
-        },
+    if (!__scratchAddonsRedux.ready) throw new Error("Redux readiness promise is unavailable");
+    if (__scratchAddonsRedux.target && !this.initialized) {
+      this.initialized = true;
+      __scratchAddonsRedux.target.addEventListener("statechanged", ({ detail }) => {
+        const newEvent = new CustomEvent("statechanged", {
+          detail: {
+            action: detail.action,
+            prev: detail.prev,
+            next: detail.next,
+          },
+        });
+        this.dispatchEvent(newEvent);
       });
-      this.dispatchEvent(newEvent);
-    });
+    }
+    return __scratchAddonsRedux.ready;
   }
 
   /**
@@ -55,8 +61,8 @@ export default class ReduxHandler extends Listenable {
    * @param {string=|string[]=} actions - the action(s) to check for.
    * @returns {Promise} a Promise resolved when the state meets the condition.
    */
-  waitForState(condition, opts = {}) {
-    this.initialize();
+  async waitForState(condition, opts = {}) {
+    await this.initialize();
     if (!__scratchAddonsRedux.target) return Promise.reject(new Error("Redux is unavailable"));
     if (condition(__scratchAddonsRedux.state)) return Promise.resolve();
     let actions = opts.actions || null;
 
@@ -1,5 +1,13 @@
 function injectRedux() {
-  window.__scratchAddonsRedux = {};
+  let resolveReduxReady;
+  window.__scratchAddonsRedux = {
+    // Create the event channel before Scratch creates its store so early
+    // userscripts can subscribe without missing later Redux events.
+    target: new EventTarget(),
+    ready: new Promise((resolve) => {
+      resolveReduxReady = resolve;
+    }),
+  };
 
   // ReDucks: Redux ducktyped
   // Not actual Redux, but should be compatible
@@ -35,13 +43,14 @@ function injectRedux() {
   let newerCompose = window.__REDUX_DEVTOOLS_EXTENSION_COMPOSE__;
   function compose(...args) {
     const scratchAddonsRedux = window.__scratchAddonsRedux;
-    const reduxTarget = (scratchAddonsRedux.target = new EventTarget());
+    const reduxTarget = scratchAddonsRedux.target;
     scratchAddonsRedux.state = {};
     scratchAddonsRedux.dispatch = () => {};
 
     function middleware({ getState, dispatch }) {
       scratchAddonsRedux.dispatch = dispatch;
       scratchAddonsRedux.state = getState();
+      resolveReduxReady();
       return (next) => (action) => {
         const nextReturn = next(action);
         const ev = new CustomEvent("statechanged", {