GTK+ XML viewer

Perfect for viewing medium-size (perhaps even large) XML files with complex annotations. I also tried conglomerate, which takes a lot more time to load the XML and tends to freeze, and the XML viewer built into Firefox, which is fast, but more difficult to handle (e.g. it unfolds all XML tags at start-up, rather than collapsing them, which makes it hard to gain understanding of the overall structure of complex XML).