Just ran into this problem myself. OSx Lion hides scrollbars while not in use to make it seem more "slick", but at the same time the issue you addressed comes up: people sometimes cannot see whether a div has a scroll feature or not.
The fix: In your css include -
::-webkit-scrollbar {
-webkit-appearance: none;
width: 7px;
}
::-webkit-scrollbar-thumb {
border-radius: 4px;
background-color: rgba(0, 0, 0, .5);
box-shadow: 0 0 1px rgba(255, 255, 255, .5);
}
/* always show scrollbars */_x000D_
_x000D_
::-webkit-scrollbar {_x000D_
-webkit-appearance: none;_x000D_
width: 7px;_x000D_
}_x000D_
_x000D_
::-webkit-scrollbar-thumb {_x000D_
border-radius: 4px;_x000D_
background-color: rgba(0, 0, 0, .5);_x000D_
box-shadow: 0 0 1px rgba(255, 255, 255, .5);_x000D_
}_x000D_
_x000D_
_x000D_
/* css for demo */_x000D_
_x000D_
#container {_x000D_
height: 4em;_x000D_
/* shorter than the child */_x000D_
overflow-y: scroll;_x000D_
/* clip height to 4em and scroll to show the rest */_x000D_
}_x000D_
_x000D_
#child {_x000D_
height: 12em;_x000D_
/* taller than the parent to force scrolling */_x000D_
}_x000D_
_x000D_
_x000D_
/* === ignore stuff below, it's just to help with the visual. === */_x000D_
_x000D_
#container {_x000D_
background-color: #ffc;_x000D_
}_x000D_
_x000D_
#child {_x000D_
margin: 30px;_x000D_
background-color: #eee;_x000D_
text-align: center;_x000D_
}
_x000D_
<div id="container">_x000D_
<div id="child">Example</div>_x000D_
</div>
_x000D_
customize the apperance as needed. Source