Ensure FloatPanel reflects closed status (#5466)

panel/layout/float.py

@@ -94,6 +94,10 @@ class FloatPanel(ListLike, ReactiveHTML):
           contentSize: `${model.width} ${model.height}`,
           onstatuschange: function() {
             data.status = this.status
+          },
+          onbeforeclose: function() {
+           data.status = 'closed'
+           return true
           }
         }
         if (data.contained) {

panel/tests/ui/layout/test_floatpanel.py

@@ -0,0 +1,27 @@
+import time
+
+import pytest
+
+from panel import FloatPanel, Spacer
+from panel.io.server import serve
+
+pytestmark = pytest.mark.ui
+
+def test_float_panel_closed_status(page, port):
+    float_panel = FloatPanel(
+        Spacer(styles=dict(background='red'), width=200, height=200),
+        Spacer(styles=dict(background='green'), width=200, height=200),
+        Spacer(styles=dict(background='blue'), width=200, height=200),
+    )
+
+    serve(float_panel, port=port, threaded=True, show=False)
+
+    time.sleep(0.2)
+
+    page.goto(f"http://localhost:{port}")
+
+    page.locator('.jsPanel-btn-close').click()
+
+    time.sleep(0.2)
+
+    assert float_panel.status == 'closed'