Hi,I met an issue while I was using xhb. When a certain property of root window being changed, it was supposed to give me an AccessError. But actually I got "thread blocked indefinitely in an STM transaction" when I waitForEvent.AFAIK, in xhb, it forks a thread to read what X server sends. Then parse and put it into a TChan. waitForEvent reads from the TChan.It is reasonable to me that if X server did not send anything, then waitForEvent would be blocked. But apparently there are some other policies in RTS.So what is that? And how should I debug it?--