This page is dedicated to all of the ENIGMA/Game Maker related plugins.
This plugin allows you to use Notepad++ as an external editor for GML script files.
1. Download and extract the plugin from http://enigma-dev.org/downloads/extras/plugins/notepad++/notepadppgml.zip
2. Download and install the latest version of Notepad++ http://sourceforge.net/project/showfiles.php?group_id=95717&package_id=102072
3. Overwrite userDefineLang.xml in C:\Users\<Your Username>\AppData\Roaming\Notepad++\
4. Add gml.xml to C:\Program Files\Notepad++\plugins\APIs\
5. Configure Notepad++ as an external code editor in Game Maker in File->Preferences->Editors
6. Inside Notepad++ turn on autocomplete in Settings->Preferences->Backup/Autocompletion
You can now use Notepad++ for externally editing gml script files, with support for code completion which shows a list of functions as you type allowing you to quickly finish code lines. The only downside is it cannot highlight constants other than the built in ones, and that includes resources. Enjoy!