Can I have an XUL panel without a shadow in my Firefox extension?

Question

XUL panels in a Firefox extension overlay always come with a shadow for free. How can I remove this shadow?

Example code for the shadow effect I don't want:

<popupset>
    <panel id="popuppanel" width="500" noautohide="true">
        <vbox>
            <label value="test"/>
            <label value=""/>
            <label value=""/>
            <label value=""/>
        </vbox>
    </panel>
</popupset>

And a screenshot:

Example image of shadow effect I don't want. http://img124.imageshack.us/img124/7766/shadowj.png

Answer 1

Use the following CSS statement:

-moz-window-shadow: none;

See also Firefox internal CSS stylesheet (mac version) for its bookmark panel.

Answer 2

I think that is part of the OS's doing. Like there is also a shadow on menus in eg. notepad. Not familiar with Vista I have to say, but it's safe to say that it's OS specific.