diff --git a/setup.cfg b/setup.cfg
index 9e75a1308..46d52025e 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -15,10 +15,10 @@ includes = glib, gio, cairo, pango, pangocairo, atk, gobject, gtk.keysyms,
 frameworks = CoreFoundation, Foundation, AppKit
 
 [isort]
-known_standard_library = unicodedata
-known_third_party = pygtk, gtk, gobject, gtk.gdk, pango, cairo, pangocairo, twisted,
-                    pytest, OpenSSL, pkg_resources, chardet, bbfreeze, win32verstamp, mock
-known_first_party = msgfmt
+known_standard_library = future_builtins
+# Ignore Windows specific modules
+known_third_party = bbfreeze, win32verstamp
+known_first_party = msgfmt, deluge
 order_by_type = true
 line_length = 120
 not_skip = __init__.py
diff --git a/tox.ini b/tox.ini
index a15d9cbb8..7c8010eb8 100644
--- a/tox.ini
+++ b/tox.ini
@@ -96,7 +96,9 @@ whitelist_externals =
 commands =
     isort --version
     python -c "import subprocess, sys; output = subprocess.check_output(\
-        'isort -q --diff --recursive deluge docs packaging *.py', shell=True);\
+        'isort -q --diff --recursive deluge docs packaging *.py\
+        -o pygtk -o gtk -o gobject -o gtk.gdk -o pango -o cairo -o pangocairo\
+        ', shell=True);\
         print output; sys.exit(bool(output))"
 
 [testenv:flake8]