[lstroud]

My recollection of XUL was that it was great when it worked, but horrific to debug.

It wasn’t also easy to make a living fixing bad VB apps (or going back to Delphi).

I’m not saying that components are a bad idea, but the 90s implementations didn’t quite realize the dream.

[asadotzler]

It was pretty easy to debug most of it with Dom Inspector and Venkman, themselves written in XUL. Even the XBL bindings and other sometimes challenging bits, were directly inspectable and editable. As a minor contributor to Mozilla's early XUL work and later Firefox's XUL work, mostly stripping XUL overlays and reducing clutter in the Firefox case, it seemed pretty straight forward to me.