Scroll bar issue in long page of ref case

Hi
  When I use  automated ref test tool to run case @https:/github.com/w3c/csswg-test/blob/master/css-color-3/t424-hsl-values-b.xht<https://github.com/w3c/csswg-test/blob/master/css-color-3/t424-hsl-values-b.xht> and related ref case, I meet two issues.

1)      The page is too long to be displayed on the screen, so scroll bar show on the page.

      On PC, the scroll bar always show.

On android mobile, the scroll bar gradually disappear. But if you slide the page, the scroll bar show again.
          When I use tool to get screenshot on android mobile, sometimes the screenshot has scroll bar, and sometimes not. This different lead to test fail.
Due to browser which I use is based on webkit, I add a CSS style to the hide the scroll bar, then get pass result. The CSS style as below:
::-webkit-scrollbar {
   width: 0px;
   height: 0px;
}


2)      Because this page is too long and show scroll bar, which need user interaction to finish the testing. It is difficult to get screenshot which  cover the entire page.

If a test needs user interaction, it cannot be automated by ref test. So, shall we rewrite (or split) the test/ref files?





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Best Regards,
Xu Jianfeng