diff -r 34d5a66fd3e0 Lib/idlelib/run.py
--- a/Lib/idlelib/run.py	Tue Jun 02 11:39:31 2015 -0400
+++ b/Lib/idlelib/run.py	Tue Jun 02 19:20:57 2015 -0400
@@ -203,8 +203,9 @@
         if tb:
             tbe = traceback.extract_tb(tb)
             print('Traceback (most recent call last):', file=efile)
-            exclude = ("run.py", "rpc.py", "threading.py", "queue.py",
-                       "RemoteDebugger.py", "bdb.py")
+            exclude = ("run.py", "rpc.py", "RemoteDebugger.py", "bdb.py")
+            if any('pdb.py' == tr[0][:-6] for tr in tbe):
+                exclude = exclude[:-1]
             cleanup_traceback(tbe, exclude)
             traceback.print_list(tbe, file=efile)
         lines = traceback.format_exception_only(typ, exc)