diff --git a/web/static/tests/core/widget.test.ts b/web/static/tests/core/widget.test.ts
index fda21f58..29870f67 100644
--- a/web/static/tests/core/widget.test.ts
+++ b/web/static/tests/core/widget.test.ts
@@ -113,10 +113,20 @@ describe("basic widget properties", () => {
     expect(renderCalls).toBe(1);
   });
 
-  test("keep a reference to env", async () => {
+  test("keeps a reference to env", async () => {
     const widget = new Widget(env);
     expect(widget.env).toBe(env);
   });
+
+  test("do not remove previously rendered dom if not necessary", async () => {
+    const widget = new Widget(env);
+    await widget.mount(fixture);
+    expect(fixture.innerHTML).toBe(`<div></div>`);
+    widget.el!.appendChild(document.createElement("span"));
+    expect(fixture.innerHTML).toBe(`<div><span></span></div>`);
+    widget.render();
+    expect(fixture.innerHTML).toBe(`<div><span></span></div>`);
+  });
 });
 
 describe("lifecycle hooks", () => {