I’ve heard that the current E2 highlighting for Notepad++ is severely out of date. I have now made a new one with original E2 colors and I have updated it with all the functions listed on the wiki.
Close N++ if it is running. Hit Windows Key + R. Type "%APPDATA%\Notepad++" without the quotes and hit enter. Extract the userDefineLang.xml file to that folder. Open N++. Under the Language menu, go to the bottom and choose Expression 2.
Example taken from the wire wiki!
Wiremod thread here.