diff --git a/src/app/(app)/orders/[id]/process/page.tsx b/src/app/(app)/orders/[id]/process/page.tsx
index d89a934..c72ed48 100644
--- a/src/app/(app)/orders/[id]/process/page.tsx
+++ b/src/app/(app)/orders/[id]/process/page.tsx
@@ -1441,14 +1441,26 @@ export default function ProcessOrderPage({ params }: { params: Promise<{ id: str
   const markInStockReady = async (supplierId: string) => {
     const supplier = suppliers.find((s) => s.id === supplierId);
     if (!supplier) return;
+    // Filter is loose on purpose: the per-row in-stock checkbox
+    // flips `item_status` to `ready_invoice` (legacy behaviour, no
+    // PO created by that path) which used to push these lines out
+    // of this filter and hide the bottom button. We want to issue
+    // the paper-trail PO from this button for ANY in-stock line
+    // that doesn't already have one, regardless of item_status,
+    // so the operator can tick the checkbox and then fire the PO
+    // from the same page without losing access to the action.
+    //
+    // The `purchase_order` guard skips lines already linked to a
+    // PO — a re-click must not duplicate.
     const inStock = items.filter(
       (it) =>
         (it.supplier || "") === supplierId &&
-        ["pending", "processed"].includes(it.item_status) &&
-        it.in_stock,
+        it.in_stock &&
+        (typeof it.purchase_order !== "string" ||
+          it.purchase_order === ""),
     );
     if (inStock.length === 0) {
-      toast.error("No in-stock items for this supplier");
+      toast.error("No in-stock items need a PO");
       return;
     }
 
@@ -2086,12 +2098,26 @@ export default function ProcessOrderPage({ params }: { params: Promise<{ id: str
                 const editable = list.filter((it) =>
                   ["pending", "processed"].includes(it.item_status),
                 );
-                if (editable.length === 0) return null;
+                // Lines that still need a stock-replenishment PO:
+                // any `in_stock=true` line without one yet, regardless
+                // of item_status. The per-row in-stock checkbox flips
+                // a line to `ready_invoice` (without creating a PO),
+                // which would otherwise push it out of `editable` and
+                // hide this button — yet the operator still needs to
+                // fire the paper-trail PO for it.
+                const needsStockPo = list.filter(
+                  (it) =>
+                    it.in_stock &&
+                    (typeof it.purchase_order !== "string" ||
+                      it.purchase_order === ""),
+                );
+                if (editable.length === 0 && needsStockPo.length === 0) {
+                  return null;
+                }
                 const nonInStockCount = editable.filter(
                   (it) => !it.in_stock,
                 ).length;
-                const inStockCount = editable.filter((it) => it.in_stock)
-                  .length;
+                const inStockCount = needsStockPo.length;
                 const isBusy =
                   sendingSupplier === supplierId ||
                   markingInStockSupplier === supplierId;