Processing instructions are now added to XUL document's DOM

[Nickolay Ponomarev]

Hey,

Bug 319654 <https://bugzilla.mozilla.org/show_bug.cgi?id=319654> was
fixed on trunk recently. Now processing instructions (e.g.
<?xml-stylesheet?> and <?xul-overlay?>) will appear in a XUL
document's DOM.

This means, you can no longer use document.firstChild in XUL scripts
to get the root element of a XUL document (as it may now return a PI
node in a document's prolog). Use document.documentElement instead.

Another change is that the xml-stylesheet and xul-overlay processing
instructions outside the prolog no longer have any effect. You may
need to change your XUL to fix this. For example,

<overlay id="downloadManagerOverlay"
xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
<?xul-overlay href="chrome://browser/content/macBrowserOverlay.xul"?>
....
</overlay>

should be changed to

<?xul-overlay href="chrome://browser/content/macBrowserOverlay.xul"?>
<overlay id="downloadManagerOverlay"
xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
....
</overlay>

Nickolay