diff --git a/pn-site/js/combobox.js b/pn-site/js/combobox.js
index 9693aa46..dca14eb2 100644
--- a/pn-site/js/combobox.js
+++ b/pn-site/js/combobox.js
@@ -110,14 +110,16 @@
 						}
 
       // Remove invalid value
-      this.input
-        .val( "" )
-        .attr( "title", value + " didn't match any item" )
-        .tooltip( "open" );
-      this.element.val( "" );
-      this._delay(function() {
-        this.input.tooltip( "close" ).attr( "title", "" );
-      }, 2500 );
+      if (value) {
+        this.input
+          .val( "" )
+          .attr( "title", value + " didn't match any item" )
+          .tooltip( "open" );
+        this.element.val( "" );
+        this._delay(function() {
+          this.input.tooltip( "close" ).attr( "title", "" );
+        }, 2500 );
+      }
       this.input.autocomplete( "instance" ).term = "";
     },