diff --git a/var/spack/repos/builtin/packages/py-matplotlib/package.py b/var/spack/repos/builtin/packages/py-matplotlib/package.py
index e56d162232..7b7239d1f0 100644
--- a/var/spack/repos/builtin/packages/py-matplotlib/package.py
+++ b/var/spack/repos/builtin/packages/py-matplotlib/package.py
@@ -80,19 +80,17 @@ def install(self, spec, prefix):
         setup_py('build')
         setup_py('install', '--prefix={0}'.format(prefix))
 
-        if str(self.version) in ['1.4.2', '1.4.3']:
-            # hack to fix configuration file
+        if '+gui' in spec:
+            # Set backend in matplotlib configuration file
             config_file = None
             for p, d, f in os.walk(prefix.lib):
                 for file in f:
                     if file.find('matplotlibrc') != -1:
                         config_file = join_path(p, 'matplotlibrc')
-                        print config_file
             if not config_file:
-                raise InstallError('could not find config file')
-            filter_file(r'backend      : pyside',
-                        'backend      : Qt4Agg',
-                        config_file)
-            filter_file(r'#backend.qt4 : PyQt4',
-                        'backend.qt4 : PySide',
-                        config_file)
+                raise InstallError('Could not find matplotlibrc')
+
+            kwargs = {'ignore_absent': False, 'backup': False, 'string': False}
+            rc = FileFilter(config_file)
+            rc.filter('^backend.*',      'backend     : Qt4Agg', **kwargs)
+            rc.filter('^#backend.qt4.*', 'backend.qt4 : PySide', **kwargs)
diff --git a/var/spack/repos/builtin/packages/python/package.py b/var/spack/repos/builtin/packages/python/package.py
index c4e6754969..57783b0542 100644
--- a/var/spack/repos/builtin/packages/python/package.py
+++ b/var/spack/repos/builtin/packages/python/package.py
@@ -133,6 +133,8 @@ def install(self, spec, prefix):
     # TODO: Once better testing support is integrated, add the following tests
     # https://wiki.python.org/moin/TkInter
     #
+    # Note: Only works if ForwardX11Trusted is enabled, i.e. `ssh -Y`
+    #
     #    if '+tk' in spec:
     #        env['TK_LIBRARY']  = join_path(spec['tk'].prefix.lib,
     #            'tk{0}'.format(spec['tk'].version.up_to(2)))