diff --git a/simgear/scene/model/SGReaderWriterXML.cxx b/simgear/scene/model/SGReaderWriterXML.cxx
index 5e0db5c4..83d6d36d 100644
--- a/simgear/scene/model/SGReaderWriterXML.cxx
+++ b/simgear/scene/model/SGReaderWriterXML.cxx
@@ -226,7 +226,7 @@ namespace {
         {
             string typeString(aNode->getStringValue("type"));
             // exclude these so we don't show yellow outlines in preview mode
-            return (typeString == "pick") || (typeString == "knob");
+            return (typeString == "pick") || (typeString == "knob") || (typeString == "slider");
         }
     };