What basis is there for it being proportional to the width/height of the scollbar?  Is there a test I can run, or a use case that I can follow to observe this behaviour?

The way it was implemented before was not consistent with Windows either.  I tried with horizontal and vertical scrollbars of various lengths, and with different thumb sizes.  However, I don't know how to make the scrollbar wider.

On Wed, Jun 18, 2008 at 2:43 AM, Rob Shearman <robertshearman@gmail.com> wrote:
Dylan Smith wrote:
> +  /* Distance beside or past the ends the scrollbar for the mouse can be dragged
> +   * away from scrollbar and still be considered in the scrollbar. */
> +#define SCROLL_DRAG_ZONE_PADDING_BESIDE    138
> +#define SCROLL_DRAG_ZONE_PADDING_PAST_END  34

This should be a proportion of the scrollbar width/height instead of
absolute values in pixels.

--
Rob Shearman