[Guy Harris <guy@xxxxxxxxxx>]

On Wed, Dec 11, 2002 at 01:31:49PM -0600, Ron Flory wrote:
>   I most often see it when 'display options' is set to 'seconds since
> previous frame'.

That's because, to get a negative time in that case, all you need is for
packet N+1 to have a time stamp before packet N; to get it for "seconds
since beginning of capture", you'd need packet N+1 to have a time stamp
before the first packet in the capture, so small "time moves backward"
glitches are more likely to cause problems with "seconds since previous
frame" than "seconds since beginning of capture".