Index: trunk/src/org/openstreetmap/josm/gui/tagging/TagCellEditor.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/tagging/TagCellEditor.java	(revision 17594)
+++ trunk/src/org/openstreetmap/josm/gui/tagging/TagCellEditor.java	(revision 17595)
@@ -105,10 +105,8 @@
         } else if (column == 1) {
 
-            if (currentTag.getValueCount() == 0) {
+            if (currentTag.getValueCount() > 1) {
                 editor.setText("");
-            } else if (currentTag.getValueCount() == 1) {
-                editor.setText(currentTag.getValues().get(0));
             } else {
-                editor.setText("");
+                editor.setText(currentTag.getValue());
             }
             initAutoCompletionListForValues(currentTag.getName());
Index: trunk/src/org/openstreetmap/josm/gui/tagging/TagCellRenderer.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/tagging/TagCellRenderer.java	(revision 17594)
+++ trunk/src/org/openstreetmap/josm/gui/tagging/TagCellRenderer.java	(revision 17595)
@@ -52,11 +52,9 @@
      */
     protected void renderTagValue(TagModel tag) {
-        if (tag.getValueCount() == 0) {
-            setText("");
-        } else if (tag.getValueCount() == 1) {
-            setText(tag.getValues().get(0));
-        } else if (tag.getValueCount() > 1) {
+        if (tag.getValueCount() > 1) {
             setText(tr("multiple"));
             setFont(fontItalic);
+        } else {
+            setText(tag.getValue());
         }
     }
Index: trunk/src/org/openstreetmap/josm/gui/tagging/TagModel.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/tagging/TagModel.java	(revision 17594)
+++ trunk/src/org/openstreetmap/josm/gui/tagging/TagModel.java	(revision 17595)
@@ -126,12 +126,5 @@
             return values.get(0);
         } else {
-            StringBuilder sb = new StringBuilder();
-            for (int i = 0; i < values.size(); i++) {
-                sb.append(values.get(i));
-                if (i + 1 < values.size()) {
-                    sb.append(';');
-                }
-            }
-            return sb.toString();
+            return String.join(";", values);
         }
     }