Apparently if the string comparison that checks whether we have reached a breakpoint is case sensitive. This is ok in Linux as File.php and fiLe.php are different things but it is pain in Windows. Many editors report the file cases incorrectly and also users can do require("FIle.php"), require("fIlE.PHP") with the same ersult for PHP but if I set a breakpoint to "filE.php" then it is not hit when the file was required as "FILE.php". In windows this comparison could be case insensitive.