[webkit-dev] Touch operation corrupts screen when specifying other than overflow:visible in css

HIDEKI YOSHIDA yoshida-hxa at necst.nec.co.jp
Wed Oct 17 00:58:02 PDT 2012


On a windows 7 tablet, PAN operation(=scroll) causes
corruption of screen.

Does anybody know how to resolve this or have the fix?

How to reproduce.
1. Prepare a HTML contents which have an element specifying
   other than "visible" to the property overflow in css.
2. Load the contents with webkit
3. Operate the touch operaion, PAN on the element.

The content in the element protrudes outside the placeholder 
for it and can disappear.

The build version
Webkit.exe on r131112 for Nightly builds

We guess Source\WebKit\win\WebView.cpp has some bugs on this 

Here is the sample contents to reproduce problem. You will see the
problem if you PAN on the field for "overflow:auto".

<HEAD><TITLE>pan with css:overflow</TITLE></HEAD>
<font size="+2">
<div style="border: 2px solid blue; padding: 5px 5px 5px 5px; overflow:visible;">
<div style="border: 2px solid red; padding: 5px 5px 5px 5px; overflow:auto;">


  Hideki Yoshida
  Embedded Software Division
  NEC System Technologies, Ltd.
    E-MAIL:yoshida-hxa at necst.nec.co.jp

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