Disconnect (at least during authentication) was not detected correctly with PuTTY 6c924ba code

Source commit: 521f8347185a16f438f4ee4048981820aa714d5e

source/core/SecureShell.cpp

@@ -1910,6 +1910,7 @@ bool __fastcall TSecureShell::EventSelectLoop(unsigned int MSec, bool ReadEventR
       unsigned int WaitResult;
       do
       {
+        CheckConnection();
         unsigned int TimeoutStep = std::min(GUIUpdateInterval, Timeout);
         if (toplevel_callback_pending(GetCallbackSet()))
         {