Fix issue on filter reference select

virtweb_frontend/src/widgets/forms/NWFSelectReferencedFilters.tsx

@@ -29,10 +29,14 @@ export function NWFSelectReferencedFilters(p: {
         <NWFilterItem
           key={n}
           value={entry}
-          onDelete={() => {
+          onDelete={
+            p.editable
+              ? () => {
                   p.selected.splice(n, 1);
                   p.onChange?.();
-          }}
+                }
+              : undefined
+          }
         />
       ))}