User-Agent: Mozilla/5.0 (Windows; Windows NT 6.1; WOW64; rv:2.0b3) Gecko/20100805 Firefox/4.0b3 Build Identifier: Mozilla/5.0 (Windows; Windows NT 6.1; WOW64; rv:2.0b3) Gecko/20100805 Firefox/4.0b3 Once on the ref URL, the page is blank. You need to reload the URL in order to see the silverlight demo. No problem in FF 4.0 b2 Reproducible: Always

I revert to changeset c7a4f2c4ba7a, then the problem is gone. So, I guess landing of patch of Bug 502937 causes the problem,

I found this to be very tricky to reproduce. In current nightlies it isn't too hard to reproduce, but as you go back into May it starts taking quite a while to reproduce. I found that clearing the cache seems to be a key part in reproducing. Given that, I was able to reproduce in a 2010-04-16 nightly, which is before changeset c7a4f2c4ba7a and bug 502937 landed. Alice, do you find it easy to reproduce, even in older builds? Do you have any tips on reproducing? Could you maybe double check your regression range?

I am creating a New Profile each time for each build run. Umm, I can not reproduce in 2010-04-16 nightly.

I think this has more to do with whether some important data is in the HTTP cache than anything else. Not a blocker unless it shows up much more frequently.

I need to try Alice's suggestion of using a new profile each time. I also want to try disabling lazyfc in current trunk to see if there are any confounding factors.

First Fail: Landing of c7a4f2c4ba7a Bug 502937 - (lazyfc) Consider doing lazy frame construction Works again: http://hg.mozilla.org/mozilla-central/rev/f203095c85de Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b5pre) Gecko/20100827 Minefield/4.0b5pre ID:20100824010818 Fixed range: http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=1d3d0dd88f0d&tochange=f203095c85de I guass fixed by landing of Bug 562698 - Pass Elements to AttributeChanged Fails again: http://hg.mozilla.org/mozilla-central/rev/0078400b865b Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b5pre) Gecko/20100827 Failing range: http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=65f20938e5d6&tochange=0078400b865b Regressed by landing of Bug 590422 - Consider getting rid of the delay line filter stuff in timer thread Works again: http://hg.mozilla.org/mozilla-central/rev/647a515c509b Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b5pre) Gecko/20100827 Minefield/4.0b5pre ID:20100827121957 Fixed range: http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=cf4d7946e2e0&tochange=647a515c509b Backed out patch of Bug 590422 - Consider getting rid of the delay line filter stuff in timer thread

This problem is still there.

Yep, i can reproduce the issue with new profile. And Comment 6 is wrong. it seems to depend on networks activities and CPU usage.

Is this still an Issue for anyone who could repro?

(In reply to comment #9) > Is this still an Issue for anyone who could repro? The URL in the summary is WFM. Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0.1) Gecko/20100101 Firefox/4.0.1 Silverlight Plug-In - File: npctrl.dll - Version: 4.0.60310.0

With Fx 8 and Silverlight 4.0.60831.0, I can no longer reproduce with the ref. URL. I close it as WFM.

Issue is resolved - clearing old keywords - qa-wanted clean-up