WebKit/Blink's (Safari/Chrome) default behaviour on MacOS since 10.7 (Mac OS X Lion) is to hide scroll bars from trackpad users when they're not in use. This can be confusing; the scroll bar is often the only visual cue that an element is scrollable.
Example (jsfiddle)
HTML<div class="frame">
Foo<br />
Bar<br />
Baz<br />
Help I'm trapped in an HTML factory!
</div>
CSS
.frame {
overflow-y: auto;
border: 1px solid black;
height: 3em;
width: 10em;
line-height: 1em;
}
WebKit (Chrome) Screenshot
How can I force a scroll bar to always be displayed on a scrollable element in WebKit?