diff --git a/pages/_lib/connection-ui.js b/pages/_lib/connection-ui.js
index 09a932ac..9fe59c05 100644
--- a/pages/_lib/connection-ui.js
+++ b/pages/_lib/connection-ui.js
@@ -1037,9 +1037,13 @@ export async function injectConnectionUI({
           direction: "asc"
         }
       });
+      ts.on('change', function() {
+        setTomSelectBorder(this);
+      });
       if (el.value) {
         ts.setValue(el.value);
       }
+      setTomSelectBorder(ts);
     }
   });
 
@@ -1257,6 +1261,14 @@ function toggleTomSelectDisabled(element, disabled) {
   }
 }
 
+function setTomSelectBorder(el){
+  if (el.getValue() === "") {
+      el.control.style.border = '2px solid red';
+  } else {
+      el.control.style.border = '1px solid #d0d0d0';
+  }
+}
+
 function getModelEl(model, modelId_prefix) {
   return document.getElementById((modelId_prefix ? modelId_prefix : '') + model);
 }