Geany

Geany is a text editor using the GTK2 toolkit with basic features of an integrated development environment.

It was developed to provide a small and fast IDE, which has only a few dependencies from other packages. It supports many file types and has some nice features.
Features:
- Syntax highlighting
- Code folding
- Symbol name auto-completion
- Construct completion/snippets
- Auto-closing of XML and HTML tags
- Call tips