Hello! That's not a message that can be toggled, it's part of the tree-view page, like the "Support Forum" label above your post. :) It's just informing you that you're viewing the source of the XML file because it's not styled with CSS, and it's the same behaviour Google Chrome has with such files. Hope it helps anyway!

I want to view an XML file attached to an e-mail in the XML format in a Firefox tab. The e-mail is forwarded to Thunderbird on my Win PC from a Super Backup Android app on my Smartphone. But when I click it in the e-mail, expecting to see a nicely formatted, HTML-like page view in a Firefox tab, all I see is the document tree view - w/ the msg you list. So is there an XML style Add-on (CSS, other styles?) which causes Firefox to display the file in a user-friendly format? Is there another way to accomplish this w/out an add-on? Hope you have the decoder ring for this puzzler. Thanks.