diff --git a/Netdisco/lib/App/Netdisco/Web/Plugin/Device/Ports.pm b/Netdisco/lib/App/Netdisco/Web/Plugin/Device/Ports.pm
index e7204188..6940b8f4 100644
--- a/Netdisco/lib/App/Netdisco/Web/Plugin/Device/Ports.pm
+++ b/Netdisco/lib/App/Netdisco/Web/Plugin/Device/Ports.pm
@@ -53,7 +53,11 @@ ajax '/ajax/content/device/ports' => require_login sub {
     }
 
     # filter for port status if asked
-    my %port_state = map {$_ => 1} (param('port_state') || ());
+    my %port_state = map {$_ => 1}
+      (ref [] eq ref param('port_state') ? @{param('port_state')}
+        : param('port_state') ? param('port_state') : ());
+
+    return unless scalar keys %port_state;
 
     if (exists $port_state{free}) {
         if (scalar keys %port_state == 1) {
diff --git a/Netdisco/share/views/ajax/device/ports.tt b/Netdisco/share/views/ajax/device/ports.tt
index 5f4a42db..1e2dcf9d 100644
--- a/Netdisco/share/views/ajax/device/ports.tt
+++ b/Netdisco/share/views/ajax/device/ports.tt
@@ -22,7 +22,7 @@
         <i class="icon-remove"></i>
         [% ELSIF row.stp == 'blocking' %]
         <i class="icon-fullscreen text-info"></i>
-        [% ELSIF row.has_column('is_free') AND row.is_free %]
+        [% ELSIF row.has_column_loaded('is_free') AND row.is_free %]
         <i class="icon-arrow-down text-success"></i>
         [% ELSIF row.up_admin == 'up' AND row.up == 'down' %]
         <i class="icon-arrow-down text-error"></i>