Turns out, this question betrays a lack of understanding of How Things Work (TM).
I asked it once, when I didn't understand how things work.
Clue: message pump. You need one.
'the main thread' doesn't really mean anything, outside of a specific context (like, say, a Win32 app with a single message pump started on the thread that executed main, as one of many examples)
Progsoc is down.