diff --git a/packages/blocks/src/v8/preview/StudioBridge.ts b/packages/blocks/src/v8/preview/StudioBridge.ts
index a1ab582f..8e06e6d3 100644
--- a/packages/blocks/src/v8/preview/StudioBridge.ts
+++ b/packages/blocks/src/v8/preview/StudioBridge.ts
@@ -11,7 +11,10 @@
  * In a frame it answers only messages from the parent window whose origin is
  * one of `trustedOrigins`. On a page that isn't framed it answers no message;
  * there it only listens for the "." shortcut (`editShortcut`), which opens the
- * page in Studio's editor, as v7's `LiveControls` did. Studio signs the editor
+ * page in Studio's editor, as v7's `LiveControls` did. A key typed in a field
+ * is left alone, also in a field inside a shadow root (a third-party widget's
+ * form), whose events reach the document with the host as their target, so the
+ * script reads the field from the event's composed path. Studio signs the editor
  * in: `/choose-editor` sends a visitor who isn't signed in to Studio's login
  * and back.
  * The binding passes Studio's origins in (`@decocms/blocks` holds no list of
@@ -117,7 +120,7 @@ if(window.self!==window.top){
   });
 }else if(s.hasAttribute("data-shortcut")){
   document.addEventListener("keydown",function(e){
-    var t=e.target;
+    var t=e.composedPath?e.composedPath()[0]:e.target;
     if(e.defaultPrevented||(t&&(t.tagName==="INPUT"||t.tagName==="TEXTAREA"||t.tagName==="SELECT"||t.isContentEditable)))return;
     if(e.key!=="."&&!(e.ctrlKey&&e.shiftKey&&e.key==="E"))return;
     e.preventDefault();
diff --git a/packages/blocks/src/v8/preview/preview.test.tsx b/packages/blocks/src/v8/preview/preview.test.tsx
index 269af19a..a6ebb26f 100644
--- a/packages/blocks/src/v8/preview/preview.test.tsx
+++ b/packages/blocks/src/v8/preview/preview.test.tsx
@@ -419,6 +419,27 @@ describe("StudioBridge", () => {
       input.remove();
     });
 
+    it("leaves typing in a field inside a shadow root alone (a third-party widget's form)", () => {
+      const open = vi.spyOn(window, "open").mockImplementation(() => null);
+      unmount = mountBridge({ site: "shop", trustedOrigins: STUDIO, editShortcut: true }, false);
+      const host = document.createElement("div");
+      document.body.appendChild(host);
+      const input = document.createElement("input");
+      host.attachShadow({ mode: "open" }).appendChild(input);
+      // The document sees the host as the target; the email's "." must still type.
+      const e = new KeyboardEvent("keydown", {
+        key: ".",
+        bubbles: true,
+        cancelable: true,
+        composed: true,
+      });
+      input.dispatchEvent(e);
+      expect(e.defaultPrevented).toBe(false);
+      expect(press({ key: ".", ctrlKey: true }, host).defaultPrevented).toBe(true);
+      expect(open).toHaveBeenCalledTimes(1);
+      host.remove();
+    });
+
     /** The choose-editor URL a Ctrl+"." opened (a plain "." navigates the tab, which jsdom can't follow). */
     function opened(open: { mock: { calls: unknown[][] } }, call = 0): Record<string, string> {
       const url = new URL(open.mock.calls[call][0] as string);