Highlighting styles can be completely customized by the end user for each code language, even allowing the changing of text area background and line number margin colors. SyntaxEditor has all the advanced editing capabilities you'd expect to find in a premium code editor, such as multiple undo/redo, block indent/outdent, line numbers, visible whitespace, word wrap, line modification marks, split views, block (rectangular) selection, customizable drag/drop, macro recording and playback, input method editor (IME) support, and more. Over 100 edit actions are included with SyntaxEditor that cover everything from basic caret movement and selection to features such as tabification, character/word/line transposition.

A powerful adornment layer system (WPF/Silverlight versions) allows for any sort of custom UI elements (images, shapes, and even controls) to be added anywhere within the text area. Animation is fully supported. Adornment layers can be set to appear before or after built-in layers, such as behind the selection. Easily add squiggle lines, background highlights, or any other decoration to text. A special kind of adornment called intra-text adornments embed themselves in-line with the text by reserving space and the text formatter adjusts the surrounding text to flow around the reserved space where the adornments render.

Extensibility is the name of the game when talking about SyntaxEditor's documents and languages. Languages are service-based objects where you can plug in any functionality you require for them. Use over 20 free languages with your SyntaxEditor implementations, or build custom syntax language implementations if needed.

Actipro offers a couple of pre-built language add-ons for SyntaxEditor that instantly give your app advanced editing functionality. The .NET Languages Add-on provides automated IntelliPrompt completion lists, parameter info, quick info, code snippets, code outlining, parsing, AST construction, syntax error reporting, a resolver, and more for C# and Visual Basic documents. The Web Languages Add-on provides automated IntelliPrompt completion lists, quick info, code outlining, parsing, AST construction, validation, syntax error reporting, end tag auto-complete, formatting, and more for XML documents, driven using XML schemas.