"Kate is a multi-document interface (MDI) text editor, available for both KDE 3 and 4. It runs on multiple Linux and Unix-like platforms, Mac OS X, and Windows. It also includes a component called KatePart, which runs inside numerous other KDE applications, including Quanta+ (on KDE 3 only), KWrite, Konqueror, and Kdevelop. Kate provides syntax highlighting for over 120 text formats, making it perfect for whatever programming language you choose.
"Kate will highlight HTML markup and underline errors, particularly when you forget to close a tag. It will also group text within tags, so that you can see what content is where. It will display folding markers, small arrows on the side, that you can use to collapse or expand a tag and its contents. To toggle folding markers, press F9. For that reason, if you are coding in XHTML, make sure to use the XML highlighting rather than HTML. It will then appropriately mark single tags that are not closed with arrows."
