This document contains answers to frequently asked questions about XUL, Mozilla's markup language for describing application's user interface.

Other FAQs you may be interested in: Extension FAQ, ...

If your question is not answered here, you can try looking for the answer in the XUL documentation or ask in the XUL newsgroup.

Are there decent visual editors for laying out XUL applications?

There are no production-quality visual editors available for XUL. The recommended way is to edit XUL by hand, possibly with the help of a good text or XML editor. Ted Mielczarek's Live XUL Editor (also part of Extension Developer's Extension) often proves useful.

A list of projects (dead and active) aiming to create a XUL IDE/editor is at wikimo:XUL:IDE.

Troubleshooting prefwindow-based options windows

This ought to be on a separate page, Preferences System Troubleshooting. It is a FAQ. Some things to check when you have issues with your prefwindow-based Options window:

  • Does each prefpane have a unique ID?
  • Are there any elements inside the <prefwindow>, before the <prefpane>s? (Putting any elements there triggers bug 296418.)
  • Are prefpanes nested correctly?
  • Does each prefpane contains a <preferences></preferences> block, even if empty?
  • Are script tags in prefpanes closed properly?
  • Does script outside <prefpane> refer to any element in <prefpane>? (The animation effect when you open the preference window will not stop, if a script outside <prefpane> refers any element inside <prefpane>, while initializing the window. If you want to access elements inside <prefpane>, you should put script in the <prefpane> or write script into "onpaneload" of the <prefpane>.)
  • Note, that prefwindow only works in chrome XUL.