Index: /trunk/src/org/openstreetmap/josm/tools/I18n.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/tools/I18n.java	(revision 3325)
+++ /trunk/src/org/openstreetmap/josm/tools/I18n.java	(revision 3326)
@@ -27,4 +27,5 @@
     private static PluralMode pluralMode = PluralMode.MODE_NOTONE; /* english default */
     private static String[] fileChooserDialogStringKeys = new String[] {
+        /* windows laf */
         "FileChooser.detailsViewActionLabelText",
         "FileChooser.detailsViewButtonAccessibleName",
@@ -50,5 +51,47 @@
         "FileChooser.upFolderAccessibleName",
         "FileChooser.upFolderToolTipText",
-        "FileChooser.viewMenuLabelText"};
+        "FileChooser.viewMenuLabelText",
+        
+        /* gtk laf */
+        "FileChooser.acceptAllFileFilterText",
+        "FileChooser.cancelButtonText",
+        "FileChooser.cancelButtonToolTipText",
+        "FileChooser.deleteFileButtonText",
+        "FileChooser.filesLabelText",
+        "FileChooser.filterLabelText",
+        "FileChooser.foldersLabelText",
+        "FileChooser.newFolderButtonText",
+        "FileChooser.newFolderDialogText",
+        "FileChooser.openButtonText",
+        "FileChooser.openButtonToolTipText",
+        "FileChooser.openDialogTitleText",
+        "FileChooser.pathLabelText",
+        "FileChooser.renameFileButtonText",
+        "FileChooser.renameFileDialogText",
+        "FileChooser.renameFileErrorText",
+        "FileChooser.renameFileErrorTitle",
+        "FileChooser.saveButtonText",
+        "FileChooser.saveButtonToolTipText",
+        "FileChooser.saveDialogTitleText",
+        
+        /* motif laf */
+        "FileChooser.cancelButtonText",
+        "FileChooser.cancelButtonToolTipText",
+        "FileChooser.enterFileNameLabelText",
+        "FileChooser.filesLabelText",
+        "FileChooser.filterLabelText",
+        "FileChooser.foldersLabelText",
+        "FileChooser.helpButtonText",
+        "FileChooser.helpButtonToolTipText",
+        "FileChooser.openButtonText",
+        "FileChooser.openButtonToolTipText",
+        "FileChooser.openDialogTitleText",
+        "FileChooser.pathLabelText",
+        "FileChooser.saveButtonText",
+        "FileChooser.saveButtonToolTipText",
+        "FileChooser.saveDialogTitleText",
+        "FileChooser.updateButtonText",
+        "FileChooser.updateButtonToolTipText"
+        };
     private static HashMap<String, String> strings = null;
     private static HashMap<String, String[]> pstrings = null;
@@ -388,5 +431,5 @@
                     String loc = UIManager.getString(key, l);
                     // only provide custom translation if it is not already localized by Java
-                    if (us.equals(loc)) {
+                    if (us != null && us.equals(loc)) {
                         UIManager.put(key, tr(us));
                     }