diff --git a/frontend/src/components/WidgetConfigDialog.tsx b/frontend/src/components/WidgetConfigDialog.tsx
index 574c1a3..0c6fa21 100644
--- a/frontend/src/components/WidgetConfigDialog.tsx
+++ b/frontend/src/components/WidgetConfigDialog.tsx
@@ -207,7 +207,12 @@ export function WidgetConfigDialog({
 	dashboardScope,
 	editWidgetId,
 }: Props) {
-	const { data: instances = [] } = useWidgetInstances(serviceId);
+	// When editing a dashboard (no serviceId), scope to dashboard-only widgets
+	// (service_id IS NULL) so service-scoped widgets don't leak into the list.
+	const { data: instances = [] } = useWidgetInstances(
+		serviceId,
+		!serviceId && dashboardScope ? "dashboard" : undefined,
+	);
 	const { data: services = [] } = useServiceInstances();
 	const { data: tasks = [] } = useTasks();
 	const saveWidget = useSaveWidgetInstance();