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 filetypes and has some nice features. 

If you need the GTK Symbol completion (removed in Geany 0.16), You can 
download them (and other tag-files from: 

    http://download.geany.org/contrib/tags/

and place them in ~/.config/geany/tags/ directory. After this you will 
need to restart Geany for this to take effect.