If auto-scrolling begins as soon as the cursor enters the sensitive zone around the edges, it is too easy for a slow-moving user to inadvertently auto-scroll.

• 如果光标一进入边界周围的敏感地带，则立即开始自动滚屏，那么对于动作慢的用户，就太容易在无意中启动自动滚屏。