+ Easily validate HTML/XHTML documents using W3C online Markup Validation Service. To use this feature, click W3C HTML icon on "Actions Bar > CH-1 > Tools > Validate" or select it on "Tools > Extra" from the main menu. [Screenshot]

+ Check CSS files for errors using W3C online CSS Validation Service. Click W3C CSS icon on "Actions Bar > CH-1 > Tools > Validate" or select it on "Tools > Extra" from the main menu. [Screenshot]

+ Ctrl+K,Ctrl+T for swapping line at the caret.

+ Ctrl+K,Ctrl+D for duplicating line at the caret.

+ Ctrl+K,Ctrl+F2 for marking selected text. Pressing it again, when there's no selection, removes the mark at the caret. Ctrl+K,Ctrl+Shift+F2 for removing all marks in the document. [Screenshot]