modified listbox conif, merge 2 column, block sorting on 1 column

data/invoices_01.json

@@ -35,9 +35,9 @@
       {"title": "id", "show": false, "priority": 5, "sort":true},
       {"title": "invoice_date", "show": true, "sort":true,"persist": true},
       {"title": "total_price", "show": true, "persist": true, "sort":true},
-      {"title": "price_currency", "show": true, "priority": 4, "sort":true },
+      {"title": "price_currency", "show": true, "priority": 4, "sort":true, "merge": "total_price", "merge_title": null },
       {"title": "translated_simulation_state_title", "show": true, "priority": 6, "sort":true  },
-      {"title": "download", "show": true, "persist": true, "actions": ["download"], "sort":"true" }
+      {"title": "download", "show": true, "persist": true, "actions": ["download"], "sort": false}
     ]
   },
   "actions": []