Index: src/org/openstreetmap/josm/gui/tagging/ac/AutoCompletingComboBox.java
===================================================================
--- src/org/openstreetmap/josm/gui/tagging/ac/AutoCompletingComboBox.java	(revision 18097)
+++ src/org/openstreetmap/josm/gui/tagging/ac/AutoCompletingComboBox.java	(working copy)
@@ -157,7 +157,6 @@
                 item = lookupItem(curText, false);
             }
 
-            setSelectedItem(item);
             if (initial) {
                 start = 0;
             }
@@ -167,6 +166,7 @@
                     selecting = true;
                     super.remove(0, size);
                     super.insertString(0, newText, a);
+                    AutoCompletingComboBox.this.setSelectedItem(item);
                     selecting = false;
                     start = size;
                     end = getLength();
@@ -186,12 +186,6 @@
             }
         }
 
-        private void setSelectedItem(Object item) {
-            selecting = true;
-            AutoCompletingComboBox.this.setSelectedItem(item);
-            selecting = false;
-        }
-
         private Object lookupItem(String pattern, boolean match) {
             ComboBoxModel<AutoCompletionItem> model = getModel();
             AutoCompletionItem bestItem = null;