diff --git a/gui/Gui/Attackwindow.py b/gui/Gui/Attackwindow.py
index 23f9f42..507701c 100644
--- a/gui/Gui/Attackwindow.py
+++ b/gui/Gui/Attackwindow.py
@@ -1,4 +1,5 @@
 #!/usr/bin/python
+from __future__ import division # 2.2+-only
 """
 	Scyther : An automatic verifier for security protocols.
 	Copyright (C) 2007 Cas Cremers
@@ -149,8 +150,8 @@ class AttackDisplay(wx.ScrolledWindow):
         self.box.Layout()
 
         step = 20
-        xn = int(virtualwidth / step) + 1
-        yn = int(virtualheight / step) + 1
+        xn = int(virtualwidth // step) + 1
+        yn = int(virtualheight // step) + 1
         self.SetScrollbars(step,step,xn,yn,0,0)
 
         """
diff --git a/gui/Gui/Preference.py b/gui/Gui/Preference.py
index ee5c882..740acd6 100644
--- a/gui/Gui/Preference.py
+++ b/gui/Gui/Preference.py
@@ -208,7 +208,7 @@ def init():
 def get(key,alt=None):
     global prefs
 
-    if prefs.has_key(key):
+    if key in prefs.keys():
         return prefs[key]
     else:
         return alt