I noticed this first in Notepad++ 5.4.3 and hoped the update would address the issue but it did not.
While editing the php 5.3 php.ini everything seems fine until I make a couple changes then all the text in the file are underlinded and code coloring (using ms-ini file) are lost.
It only seems to happen with the php.ini 5.3; previous versions are unaffected on my system.
I'm running...
2009-07-06 20:40:22 UTC in Notepad++