private void defineChildNodes() {
			parsed = true; // To avoid the reload.
			children = file.listFiles();
			if( children != null ){
				for (File f : children) {
					if (!f.getName().startsWith(".")) {
						// Ignore hidden and special files.
						if (f.isDirectory()) {
							add(new FileTreeExpander(f));
						}
					}
				}
			}
			else {
				// Ignore the bugs: this is a sample.
				children = new File[0];
			}
		}