Issue #25173: Replace 'master' with 'parent' in tkinter.messagebox calls.
This associates the message box with the widget and is better for Mac OSX.
Patch by Mark Roseman.
diff --git a/Lib/idlelib/run.py b/Lib/idlelib/run.py
index d023e28..466c61e 100644
--- a/Lib/idlelib/run.py
+++ b/Lib/idlelib/run.py
@@ -164,7 +164,7 @@
         tkMessageBox.showerror("IDLE Subprocess Error", msg, parent=root)
     else:
         tkMessageBox.showerror("IDLE Subprocess Error",
-                               "Socket Error: %s" % err.args[1])
+                               "Socket Error: %s" % err.args[1], parent=root)
     root.destroy()
 
 def print_exception():