Opening a serial port in use causes the program to crash

[NAW77]

The original Putty 0.63 displays a window telling you that COMx is currently in use when you have another program or session using that port.
The currenty t020 build of Putty Tray just crashes if you use the same port "A problem caused the program to stop working correctly. Please close the program" with the option to Close or Debug.
If I select to debug with VStudio then I get "Unhandled exception at 0x00B38C8E in putty.exe: 0xC0000005: Access violation reading location 0xE8ED6472."

This issue happens all the time on Win8.1-x64 with a USB FTDI chipset device.

[FauxFaux]

Yeah, I can reproduce this. It's a bug in GH-110: ada3951#diff-88776592a9f52e2b3f2939253efbc5ecL321

The error handling here isn't great and realhost is ending up unset for some types of connections. I'll re-think the error handling later.