Better handle user dismissing the verifaction dialog.

EDMarketConnector.py

@@ -226,6 +226,7 @@ class AppWindow:
             self.session.verify(code)
         except Exception as e:
             if __debug__: print_exc()
+            self.button['state'] = tk.NORMAL
             self.status['text'] = unicode(e)
         else:
             return self.getandsend()	# try again

companion.py

@@ -166,6 +166,8 @@ class Session:
             return r.status_code
 
     def verify(self, code):
+        if not code:
+            raise VerificationRequired()
         r = self.session.post(URL_CONFIRM, data = {'code' : code}, timeout=timeout)
         r.raise_for_status()
         # verification doesn't actually return a yes/no, so log in again to determine state

prefs.py

@@ -331,6 +331,8 @@ class AuthenticationDialog(tk.Toplevel):
         for child in frame.winfo_children():
             child.grid_configure(padx=5, pady=5)
 
+        self.protocol("WM_DELETE_WINDOW", self._destroy)
+
         # wait for window to appear on screen before calling grab_set
         self.wait_visibility()
         self.grab_set()
@@ -344,3 +346,7 @@ class AuthenticationDialog(tk.Toplevel):
         code = self.code.get().strip()
         self.destroy()
         if self.callback: self.callback(code)
+
+    def _destroy(self):
+        self.destroy()
+        if self.callback: self.callback(None)