src/vs/workbench/services/dialogs/browser/simpleFileDialog.ts/SimpleFileDialog/pathAppend
class SimpleFileDialog:	private pathAppend(uri: URI, additional: string): string {
		if ((additional === '..') || (additional === '.')) {
			const basePath = this.pathFromUri(uri, true);
			return basePath + additional;
		} else {
			return this.pathFromUri(resources.joinPath(uri, additional));
		}
	}