diff --git a/frontend/src/components/SettingsModal.tsx b/frontend/src/components/SettingsModal.tsx
index 62b14e7..af7c7b8 100644
--- a/frontend/src/components/SettingsModal.tsx
+++ b/frontend/src/components/SettingsModal.tsx
@@ -3394,9 +3394,16 @@ export function SettingsModal({ onClose, onSaved, initialSection, onMainPaneChan
   // register — the output on/off. The voltage and current SET points are shown
   // because they are worth seeing, and are not editable here: they belong to the
   // supply's front panel, and a logbook that can set them can set them wrong.
+  // NO HOOKS IN HERE. This panel is called as a plain function, like its
+  // neighbours — PANELS[x]() — so a useState of its own lands in SettingsModal's
+  // hook list and only while this section is open. React counts those, and it
+  // stopped drawing the moment the section was clicked (error #310, "rendered
+  // more hooks than during the previous render"). The COM ports come from the
+  // list SettingsModal already loads for the Winkeyer panel: one machine, one
+  // set of serial ports, loaded once.
   function PSUPanelSettings() {
-    const [ports, setPorts] = useState<string[]>([]);
-    useEffect(() => { ListSerialPorts().then((p) => setPorts((p ?? []) as string[])).catch(() => setPorts([])); }, []);
+    const ports = wkPorts;
+    const setPorts = setWkPorts;
     return (
       <>
         <SectionHeader title={t('psu.title')} hint={t('psu.hint')} />