User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:56.0) Gecko/20100101 Firefox/56.0 Build ID: 20170719030206 Steps to reproduce: 1) Open https://www.songsterr.com/a/wsa/tears-for-fears-everybody-wants-to-rule-the-world-tab-s19814t1 2) Wait for it to finish loading and hit play on the right. Actual results: The green marker moving over the song regularly disappears when HWA is on. Expected results: The green marker should remain visible, as it does in other browsers and with HWA off.

Whst do you mean by HWA being on? Is this site playing a video?

By HWA I meant hardware acceleration. It's not playing a video. One of the Graphics components is probably more appropriate here.

It's not playback then. At this stage I'll assume it's graphics.

Still wondering what.made you assume it was a Hwa issue. Eg. One step to reproduce without the problem appearing, and one with the problem.

You can toggle hardware acceleration on about:preferences in the 'General' settings under 'Performance'. First uncheck 'Use recommended performance settings', then check/uncheck 'Use hardware acceleration when available'. I think you need to restart the browser before the setting takes effect, so make sure you do that. Do note that hardware acceleration may not be available depending on your hardware/platform.

Can no longer reproduce this after upgrading to 20170722030204.

Now it's happening again for me on 20170723030206. I suspect it wasn't gone from 20170722030204 at all, but that there's another factor that triggers the bug that I'm overlooking. I'll try to do more thorough testing.

I confirmed that the problem happened on latest nightly. It seems like AdvancedLayer specific bug. When I set "layers.mlgpu.dev-enabled" from about:config, the problem did not happen.

(In reply to Sotaro Ikeda [:sotaro] from comment #8) > I confirmed that the problem happened on latest nightly. It seems like > AdvancedLayer specific bug. When I set "layers.mlgpu.dev-enabled" from > about:config, the problem did not happen. Correction: When I set "layers.mlgpu.dev-enabled" to false from about:config, the problem did not happen.

Bug 1381666 might be a related bug.

:dvander, can you comment to the bug?

Advanced Layers was assuming that it could skip over container layers if their visible bounds didn't overlap with the invalid region. The idea is we could skip recursing down large subtrees. Unfortunately it doesn't work since visible regions on containers are not updated for async transforms or animations. We do recompute the bounds of containers with intermediate surfaces, but not pass-through containers. We could tweak this optimization to only apply to fixed-up containers, or we could fix-up all containers... but instead, let's just remove it for now. I doubt it buys us much.

Pushed by danderson@mozilla.com: https://hg.mozilla.org/integration/mozilla-inbound/rev/e9de905b23fa Always visit children of container layers, in case they have asynchronous animations outside of the precomputed visible bounds. (bug 1382382, r=mattwoodrow)