diff --git a/mpl_interactions/controller.py b/mpl_interactions/controller.py
index ac68584..5db41a7 100644
--- a/mpl_interactions/controller.py
+++ b/mpl_interactions/controller.py
@@ -393,7 +393,7 @@ def gogogo_controls(
         if extra_controls is None:
             extra_controls = [ctrl_context]
         else:
-            extra_controls.append[ctrl_context]
+            extra_controls.append(ctrl_context)
 
     # Squash controls + extra_controls and make sure we have a unique controller object
 
diff --git a/tests/test_controls.py b/tests/test_controls.py
index cf07d4a..a6a31f8 100644
--- a/tests/test_controls.py
+++ b/tests/test_controls.py
@@ -55,3 +55,17 @@ def f2(x, amp, tau, beta):
     ctrls.save_animation(str(tmp_path / "animation-amp.gif"), fig, "amp", N_frames=10)
     ctrls.save_animation(str(tmp_path / "animation-beta.gif"), fig, "beta")
     ctrls.save_animation(str(tmp_path / "animation-tau.gif"), fig, "tau")
+
+
+def test_scalar_inside_context():
+    x = np.random.randn(20)
+    y = 2 * x + np.random.randn(20) / 2
+
+    x2 = np.random.randn(20)
+    y2 = -2 * x2 - np.random.randn(20) / 2
+
+    fig, ax = plt.subplots()
+    ctrls = iplt.scatter(x, y, s=(10, 1000))
+    # this shouldn't fail
+    with ctrls:
+        _ = iplt.scatter(x2, y2, s=ctrls["s"], ax=ax)