--- a/browser/components/extensions/test/browser/browser_ext_devtools_inspectedWindow_eval_bindings.js
+++ b/browser/components/extensions/test/browser/browser_ext_devtools_inspectedWindow_eval_bindings.js
@@ -133,16 +133,44 @@ add_task(async function test_devtools_in
             resolve(m.node);
             jsterm.hud.off("new-messages", onThisMessage);
             return;
           }
         });
       });
       let objectInspectors = [...messageNode.querySelectorAll(".tree")];
       is(objectInspectors.length, 1, "There is the expected number of object inspectors");
+
+      // We need to wait for the object to be expanded so we don't call the server on a closed connection.
+      const [oi] = objectInspectors;
+      let nodes = oi.querySelectorAll(".node");
+
+      ok(nodes.length >= 1, "The object preview is rendered as expected");
+
+      // The tree can still be collapsed since the properties are fetched asynchronously.
+      if (nodes.length === 1) {
+        info("Waiting for the object properties to be displayed");
+        // If this is the case, we wait for the properties to be fetched and displayed.
+        await new Promise(resolve => {
+          const observer = new MutationObserver(mutations => {
+            resolve();
+            observer.disconnect();
+          });
+          observer.observe(oi, {childList: true});
+        });
+
+        // Retrieve the new nodes.
+        nodes = oi.querySelectorAll(".node");
+      }
+
+      // We should have 3 nodes :
+      //   ▼ Object { testkey: "testvalue" }
+      //   |  testkey: "testvalue"
+      //   |  ▶︎ __proto__: Object { … }
+      is(nodes.length, 3, "The object preview has the expected number of nodes");
     } else {
       const options = await new Promise(resolve => {
         jsterm.once("variablesview-open", (evt, view, options) => resolve(options));
       });
 
       const objectType = options.objectActor.type;
       const objectPreviewProperties = options.objectActor.preview.ownProperties;
       is(objectType, "object", "The inspected object has the expected type");