Mark Hammond writes: Tim's suggestion of copying the font for the
CallTipWindow from the text control makes sense, and actually makes
the control look better IMO.
diff --git a/Tools/idle/CallTipWindow.py b/Tools/idle/CallTipWindow.py
index 71d6755..cbeab8c 100644
--- a/Tools/idle/CallTipWindow.py
+++ b/Tools/idle/CallTipWindow.py
@@ -25,7 +25,8 @@
         tw.wm_overrideredirect(1)
         tw.wm_geometry("+%d+%d" % (x, y))
         label = Label(tw, text=self.text, justify=LEFT,
-                      background="#ffffe0", relief=SOLID, borderwidth=1)
+                      background="#ffffe0", relief=SOLID, borderwidth=1,
+                      font = self.widget['font'])
         label.pack()
                       
     def hidetip(self):