> the assumption: you will actually exit the thread through 
> the top-level thread function.

No, no. The bug fixed some time ago was due to threads 
trying to resolve an hostname, and the main thread trying 
to exit at the same time because there were an error.

> I'm not going to waste any more of my valuable time 
helping

So don't waste my time either. The Windows GUI is horribly 
coded, I know it, and if I had some time I would rewrite it 
from scratch. But I don't have the necessary free hours to 
do it, and the Linux version is also taking a part of this 
free time.

HTTrack is open source, and under GPL - you can write your 
own GUI and release it. It may even replace the exiting one 
if it is better.