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 21:40:59 2012 -0500
@@ -60,6 +60,7 @@
         self.frame = None
         self.make_gui()
         self.interacting = 0
+        self.closing = False
 
     def run(self, *args):
         try:
@@ -69,17 +70,30 @@
             self.interacting = 0
 
     def close(self, event=None):
-        if self.interacting:
+        if self.stackviewer:
+            self.stackviewer.close()
+            self.stackviewer = None
+
+        if self.interacting or self.pyshell.executing:
+            self.closing = True
+            self.quit()  # .quit() eventually resumes at .mainloop
+                         # in self.interaction()
+        else:
+            self.top.destroy()
+
+    def wm_close(self, event=None):
+        # Callback for closing the debugger from the debugger window.
+        if self.interacting or self.pyshell.executing:
             self.top.bell()
-            return
-        if self.stackviewer:
-            self.stackviewer.close(); self.stackviewer = None
-        # Clean up pyshell if user clicked debugger control close widget.
-        # (Causes a harmless extra cycle through close_debugger() if user
-        # toggled debugger from pyshell Debug menu)
-        self.pyshell.close_debugger()
-        # Now close the debugger control window....
-        self.top.destroy()
+            self.bquit.flash()  # Let user know to click "Quit"
+        else:
+            self.pyshell.close_debugger()
+
+    def set_focus(self, event=None):
+        # Helper for ScriptBinding
+        self.bcont.flash()
+        self.top.focus()
+        self.top.lift()
 
     def make_gui(self):
         pyshell = self.pyshell
@@ -88,8 +102,8 @@
         self.top = top = ListedToplevel(root)
         self.top.wm_title("Debug Control")
         self.top.wm_iconname("Debug")
-        top.wm_protocol("WM_DELETE_WINDOW", self.close)
-        self.top.bind("<Escape>", self.close)
+        top.wm_protocol("WM_DELETE_WINDOW", self.wm_close)
+        self.top.bind("<Escape>", self.wm_close)
         #
         self.bframe = bframe = Frame(top)
         self.bframe.pack(anchor="w")
@@ -103,7 +117,7 @@
         bl.append(b)
         self.bret = b = Button(bframe, text="Out", command=self.ret)
         bl.append(b)
-        self.bret = b = Button(bframe, text="Quit", command=self.quit)
+        self.bquit = b = Button(bframe, text="Quit", command=self.quit)
         bl.append(b)
         #
         for b in bl:
@@ -193,6 +207,9 @@
         #
         self.top.wakeup()
         self.root.mainloop()
+        if self.closing:
+            self.top.destroy()
+            return
         #
         for b in self.buttons:
             b.configure(state="disabled")
diff -r 5c2aabd7619b Lib/idlelib/PyShell.py
--- a/Lib/idlelib/PyShell.py	Fri Oct 05 22:16:55 2012 +0300
+++ b/Lib/idlelib/PyShell.py	Mon Oct 08 21:40:59 2012 -0500
@@ -716,7 +716,8 @@
     def runcode(self, code):
         "Override base class method"
         if self.tkconsole.executing:
-            self.interp.restart_subprocess()
+            if use_subprocess:
+                self.restart_subprocess()
         self.checklinecache()
         if self.save_warnings_filters is not None:
             warnings.filters[:] = self.save_warnings_filters
@@ -923,10 +924,11 @@
             db.close()
             if self.interp.rpcclt:
                 RemoteDebugger.close_remote_debugger(self.interp.rpcclt)
-            self.resetoutput()
-            self.console.write("[DEBUG OFF]\n")
             sys.ps1 = ">>> "
-            self.showprompt()
+            if not self.closing:
+                self.resetoutput()
+                self.console.write("[DEBUG OFF]\n")
+                self.showprompt()
         self.set_debugger_indicator()
 
     def open_debugger(self):
diff -r 5c2aabd7619b Lib/idlelib/ScriptBinding.py
--- a/Lib/idlelib/ScriptBinding.py	Fri Oct 05 22:16:55 2012 +0300
+++ b/Lib/idlelib/ScriptBinding.py	Mon Oct 08 21:40:59 2012 -0500
@@ -83,8 +83,7 @@
                 return False
         return True
 
-    def checksyntax(self, filename):
-        self.shell = shell = self.flist.open_shell()
+    def checksyntax(self, filename, shell):
         saved_stream = shell.get_warning_stream()
         shell.set_warning_stream(shell.stderr)
         f = open(filename, 'rb')
@@ -135,16 +134,21 @@
         directory to the directory of the module being executed and also
         add that directory to its sys.path if not already included.
         """
+        shell = self.flist.open_shell()
+        db = shell.interp.getdebugger()
+        if db and shell.executing:
+            db.set_focus()
+            return 'break'  # Don't run if already debugging...
 
         filename = self.getfilename()
         if not filename:
             return 'break'
-        code = self.checksyntax(filename)
+        code = self.checksyntax(filename, shell)
         if not code:
             return 'break'
         if not self.tabnanny(filename):
             return 'break'
-        interp = self.shell.interp
+        interp = shell.interp
         if PyShell.use_subprocess:
             interp.restart_subprocess(with_cwd=False)
         dirname = os.path.dirname(filename)