diff --git a/tabs/transponder.css b/tabs/transponder.css
index f903c158..d5e0e969 100644
--- a/tabs/transponder.css
+++ b/tabs/transponder.css
@@ -84,4 +84,5 @@
 
 .tab-transponder select {
     min-width: 100px;
+    border: 1px solid silver;
 }