https://github.com/editorconfig/editorconfig/issues/144

fix-144-case-sensitive.diff

--- a/plugin/editorconfig-core-py/editorconfig/ini.py
+++ b/plugin/editorconfig-core-py/editorconfig/ini.py
@@ -17,10 +17,10 @@ import re
 from codecs import open
 import posixpath
 from os import sep
-from os.path import normcase, dirname
+from os.path import dirname
 
 from editorconfig.exceptions import ParsingError
-from editorconfig.fnmatch import fnmatch
+from editorconfig.fnmatch import fnmatchcase
 from editorconfig.odict import OrderedDict
 from editorconfig.compat import u
 
@@ -59,7 +59,7 @@ class EditorConfigParser(object):
 
     def matches_filename(self, config_filename, glob):
         """Return True if section glob matches filename"""
-        config_dirname = normcase(dirname(config_filename)).replace(sep, '/')
+        config_dirname = dirname(config_filename).replace(sep, '/')
         glob = glob.replace("\\#", "#")
         glob = glob.replace("\\;", ";")
         if '/' in glob:
@@ -68,7 +68,7 @@ class EditorConfigParser(object):
             glob = posixpath.join(config_dirname, glob)
         else:
             glob = posixpath.join('**/', glob)
-        return fnmatch(self.filename, glob)
+        return fnmatchcase(self.filename.replace(sep, '/'), glob)
 
     def read(self, filename):
         """Read and parse single EditorConfig file"""

The removal of normcase makes path shortening not available: X:\a\b\..\c would not be shortened. Anyway, see my new comment in editorconfig/editorconfig#144.