diff --git a/gui/Attackwindow.py b/gui/Attackwindow.py
index 90503c5..934befb 100644
--- a/gui/Attackwindow.py
+++ b/gui/Attackwindow.py
@@ -21,7 +21,7 @@ class AttackDisplay(wx.ScrolledWindow):
 
         wx.ScrolledWindow.__init__(self,parent,id=-1)
         # Wait for the attack to be computed
-        while not attack.pngfile:
+        while not attack.file:
             time.sleep(1)
 
         self.Bind(wx.EVT_SIZE, self.OnSize)
@@ -32,7 +32,7 @@ class AttackDisplay(wx.ScrolledWindow):
         self.hbox.Add(self.box,1,wx.ALIGN_CENTER)
         self.SetSizer(self.hbox)
 
-        filename = attack.pngfile
+        filename = attack.file
         self.original = wx.Image(filename,wx.BITMAP_TYPE_PNG)
 
 
diff --git a/gui/Scytherthread.py b/gui/Scytherthread.py
index 33c3883..70b3320 100644
--- a/gui/Scytherthread.py
+++ b/gui/Scytherthread.py
@@ -100,7 +100,8 @@ class AttackThread(threading.Thread):
         pw.write(attack.scytherDot)
         pw.close()
         pr.close()
-        attack.pngfile = fpname2  # this is where the file name is stored
+        attack.file = fpname2  # this is where the file name is stored
+        attack.filetype = "png"
 
 #---------------------------------------------------------------------------
 
@@ -135,6 +136,14 @@ class VerificationWindow(wx.Dialog):
 
 class ResultWindow(wx.Frame):
 
+    """
+    Displays the claims status and contains buttons to show the actual
+    attack graphs
+
+    TODO: this really should have a statusbar, and maybe a second tab
+    for any error output.
+    """
+
     def __init__(
             self, parent, parentwindow, title, pos=wx.DefaultPosition, size=wx.DefaultSize, 
             style=wx.DEFAULT_DIALOG_STYLE
@@ -156,14 +165,9 @@ class ResultWindow(wx.Frame):
         w.Show(True)
 
     def onCloseWindow(self,evt):
-        # TODO we should kill self.thread
+        """ TODO we should kill self.thread """
 
         # Clean up
-        for cl in self.parent.claims:
-            for attack in cl.attacks:
-                if attack.pngfile:
-                    os.unlink(attack.pngfile)
-                    attack.pngfile = None
         self.parent.claims = None
 
         self.Destroy()