the simple code is as follows, in chrome mobile mode
<div style="border:1px solid -sharp000;height:667px;width:375px;overflow:scroll">
<div style="min-height:667px">
<div style="height:10px;margin-bottom:10px"></div>
</div>
</div>
A scroll bar appears when margin-bottom:10px is removed, but even if the div is added to the margin, the parent div cannot be propped apart. Why is there a scroll bar?