On 09/23/2013 11:46 AM, Joakim Gebart wrote:
> 2013/9/22 Alexander Kapshuk <alexander.kapshuk@gmail.com 
> <mailto:alexander.kapshuk@gmail.com>>
>
>     On 09/21/2013 06:32 PM, Al wrote:
>     > Bruce Hill wrote:
>     >> I have "Use smooth scrolling" checked and no such wavy line
>     anywhere.
>     >
>     > Hmmm....
>     >
>     > I just tried Firefox, and get the wavy line when "Use smooth
>     scolling
>     > is checked (scrolling with the mouse wheel). It goes away when
>     unchecked.
>     >
>     > Did the same in Thunderbird, and I don't see the wavy line, no
>     matter
>     > what the setting.
>     >
>     > Al
>     >
>     >
>     Having the "Use smooth scrolling" option unchecked in both Firefox and
>     Thunderbird seems to have fixed the 'wavy line' problem for me.
>
>     Thanks.
>
>
> I'm guessing the wavy line that you describe is 'tearing' that appears 
> when the display is not synced to the framebuffer, i.e. "vsync". I 
> believe some of the graphics drivers are not even capable of vsync 
> currently in X11, but I'm not certain.
>
> /JG
That sounds right. I just wasn't sure how to best put it into technical 
terms.

Thanks.