Question

I open my Firefox extension window in a browser’s tab. Is it possible to set a favicon for that tab?

Answer 1

The code from the Mozilla site does not work correctly – it produces the following error message: “Warning: XUL box for box element contained an inline link child, forcing all its children to be wrapped in a block”. If this code is placed between ‘window’ tags it messes up all other controls on the window. If it is placed between ‘box’ tags, window controls are rendered fine, but still there is this error message. The problem was solved by adding the display property and setting it to “none”.
The working code looks like this:

<window xmlns="mozilla.org/keymaster/gatekeeper/there.is.only.xul";
        xmlns:html="w3.org/1999/xhtml">
<!-- Icon from chrome -->
<html:link rel="icon" href="chrome://myExtension/content/path/to/favicon.png"
           style="display:none"/>