[Webkit-unassigned] [Bug 40811] New: -webkit-transition for opacity doesn't work properly on first pass when element display 'none' on page load

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=40811

           Summary: -webkit-transition for opacity doesn't work properly
                    on first pass when element display 'none' on page load
           Product: WebKit
           Version: 528+ (Nightly build)
          Platform: PC
        OS/Version: All
            Status: NEW
          Severity: Normal
          Priority: P2
         Component: Layout and Rendering
        AssignedTo: webkit-unassigned at lists.webkit.org
        ReportedBy: bfulgham at webkit.org


The attached test case attempts to animate the reveal of some hidden page content (display type set to none) using a fade-in transition.

Expected behavior would be for the hidden content to fade-in on the first pass:
1. Element display type changed from 'none' to '' (opacity is 0 initially).  If this element was part of a page with more content, I would expect downstream elements to shift down by the size of the hidden element (though the region will show blank due to zero opacity.)
2. Element will transition (using -webkit-transition) from opacity 0 to opacity 1.
3. Animation completes
4. Repeating the "Show/hide" button causes the element to fade out.
5. Repeating the "Show/hide" button causes the element to fade in.

Actual behavior on Windows Safari 4.0 - 5.0, Mac Safari 5.0 (and probably prior), and WinCairo port is as follows:
1. Element display type changed from 'none' to ''.  Although opacity is 0 initially, the element pops into full existence with no animation.
2. If the "Show/hide" button is pressed, element fades out as expected.
3. If the "Show/hide" button is pressed again, element fades in as expected.

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