There has to be some gap of clock cycles between the unblocking of signals and the next instruction carried by the process, and any occurrence of a signal in this window of time is lost.
从消除信号阻塞到进程执行下一个指令之间，必然会有时钟周期间隙，任何在此时间窗口发生的信号都会丢掉。
2
An element in one of the columns with a top margin will see that margin pushed above the header, resulting in a gap between the top of the window and the top of the header section.