diff -r 5c2aabd7619b Lib/idlelib/Debugger.py
--- a/Lib/idlelib/Debugger.py	Fri Oct 05 22:16:55 2012 +0300
+++ b/Lib/idlelib/Debugger.py	Mon Oct 08 01:56:56 2012 -0500
@@ -69,7 +69,8 @@
             self.interacting = 0
 
     def close(self, event=None):
-        if self.interacting:
+        if self.interacting or self.pyshell.executing:
+            # See issue15348 for issues dealing with the subprocess
             self.top.bell()
             return
         if self.stackviewer:
diff -r 5c2aabd7619b Misc/NEWS
--- a/Misc/NEWS	Fri Oct 05 22:16:55 2012 +0300
+++ b/Misc/NEWS	Mon Oct 08 01:56:56 2012 -0500
@@ -39,6 +39,8 @@
 Library
 -------
 
+- Issue #15348: IDLE debugger should not close when active if using a subprocess.
+
 - Issue #16089: Allow ElementTree.TreeBuilder to work again with a non-Element
   element_factory (fixes a regression in SimpleTAL).