Index: trunk/src/org/openstreetmap/josm/actions/OpenFileAction.java
===================================================================
--- trunk/src/org/openstreetmap/josm/actions/OpenFileAction.java	(revision 8756)
+++ trunk/src/org/openstreetmap/josm/actions/OpenFileAction.java	(revision 8757)
@@ -115,5 +115,6 @@
                         @Override
                         public boolean accept(File dir, String name) {
-                            return name.startsWith(file.getName()) && fileFilter.accept(new File(dir, name));
+                            return name.startsWith(file.getName())
+                                    && fileFilter != null && fileFilter.accept(new File(dir, name));
                         }
                     });