WPF

Using Commands:
http://www.wpf-tutorial.com/commands/using-commands/

Markup Extensions:
https://docs.microsoft.com/en-us/dotnet/framework/wpf/advanced/markup-extensions-and-wpf-xaml
https://docs.microsoft.com/en-us/dotnet/framework/wpf/advanced/binding-markup-extension

Avalon Edit:
http://danielgrunwald.de/coding/AvalonEdit/rendering.php
https://www.codeproject.com/Articles/42490/Using-AvalonEdit-WPF-Text-Editor
http://avalonedit.net/