Bug 47673 – large values in CSS mishandled at zoom levels 2 and above

• Component: Layout and Rendering
• Status: UNCONFIRMED

[Rob L.]

Created attachment 70741 [details]
screenshot of supplied URL zoomed two times with Cmd+

Noticed this while working with the jQuery UI "buttonset" component.

This component uses JavaScript to create an alternate UI for managing a selection in a radio button group. When initialized, it assigns a class "ui-helper-hidden-accessible" to the radio button, which provides the CSS properties:

position: absolute;
left: -99999999px;

WebKit appears to mishandle the -99999999px value after zooming two or more times with Cmd+ or Ctrl+: the radio button becomes visible, even though it should still be thousands of pixels left of the left edge of the viewport.

Oddly the web inspector shows this value for the element instead of the -99999999px supplied in the stylesheet.

left: -1e+08px;

Observed this on latest Chrome and Safari on both OS X 10.6 and Windows XP.

This problem does not occur if you change the left: value to -9999px, hence the bug description's claim that the problem is WebKit mishandling large values.