Flash Player freezes after browser tab change

[felipe_snews]

Hi,

I have a web application running on Flash and recently some users are reporting that sometimes when they change the browser tab and then return to the app tab, it doesn't respond to any click.

After some tests, I discovered that the app isn't crashing, because when I click on a button that dispatches a request to the server, the server receives this request, but the button doesn't show visually that is being pressed.

I was able to reproduce the same freeze outside of my app with a single FLVPlayback running a video. But it isn't related to the video component because I can also reproduce by starting some "setInverval()" calls executing something with a really small interval just to simulate something running in the Flash Player.

This link I found on the web can be used as an example: http://www.dhs.state.il.us/accessibility/tests/flash/video.html. In a separated browser window, open this link in a tab and open another empty tab. Keep the Ctrl+TAB keys pressed to keep switching between the two tabs for some time. Usually, when the video is playing, it freezes after a few seconds.

So far I have personally seen this problem happen only in Chrome, but I have been told that the same thing happened in other browsers.

My Chrome version is 60.0.3112.90, running Flash Player 26.0.0.151 (both Windows 10 and OSX Sierra).

I haven't found anyone reporting a problem like this recently. Can you guys give me some help?

[qLipp]

This is an issue my QA team (and myself) have been "dealing with" for months now, in Chrome.   It is/was intermittent in that only sometimes our game would freeze upon tab switch, but repeatedly hitting ctrl-tab rapidly would 99.999% of the time reproduce the issue.

What's universally consistent, however, is the remedy:  resizing the window will _always_ bring back the game.  As such, forcing a DOM redraw fixed this problem for us, but i'll admit its a stupid thing we shouldn't have to do hahha.

try this:  https://play.hdpoker.com/

Our fix is still in dev so you can see it at the above link for now, until we deploy it.   If you have a Facebook account you can use for testing things, log in with it.   Open up a second tab, then hit ctrl-tab repeatedly really fast to get it to freeze.

[jeromiec83223024]

This thread has always been a little convoluted, and I'm not clear on what platform(s) are still affected.

I'm not able to reproduce this with MacOS 10.13.3 on Chorme Version 64.0.3282.186 (Official Build) (64-bit) or Firefox 58.0.2 (64-bit) with Flash Player 28.0.0.161

[tufikc12551576]

This problem is present in Windows 10 /Chrome Version 68.0.3440.106 (Official Build) (64-bit)

[elishag80417505]

Hi guys,

I am also having a similar issue (as are others using chrome in my organisation). Flash player freezes (visually) on screen when using Chrome browser until something refreshes it. I have tested in internet explorer and do not have the same issue.

Let me explain further.

We have online learning content within flash player that launches a few external links. These external links open in a new tab. When we close that tab and return back to our original content, it is frozen. The mouse moves, but visually, it is completely frozen. Nothing appears to happen if we click on buttons, rollovers and animations don't work etc.

However - if we scale the browser window or move it, or even open the developer console (anything to 'wake' the browser up essentially), it comes back to life where it should have been.

To me it seems like it is just the visual image that is freezing - the back end still is all working.

As an example, if its frozen and i click where a 'next page' button is, the page still seems frozen - but when i wake the browser up again by resizing it - the page refreshes and i am at the next page already (as though it had all worked properly when I clicked on the button - just that the visuals had frozen).

Here are the tech details for you:

OS: Windows 10 Professional

Chrome version: Version 68.0.3440.106 (Official Build) (64-bit)

Flash Version: 30.0.0.134

Any help here would be fantastic  jeromiec83223024​

Thanks,

[jeromiec83223024]

Thanks.  I can reproduce this on Win10/Chrome.  I'll get a bug open.

[tufikc12551576]

If you have the control of the code, one quick way to fix it (worked for us) is resizing the HTML when the user comes back to the page. Of course, that is a patch but could you help you while Adobe fixes the problem.

document.addEventListener('visibilitychange', function(){

            if(!document.hidden) {

                document.querySelector('html').style.width="99.9%";

                setTimeout( function(){

                    document.querySelector('html').style.width="100%";

                }, 1000);

            }

        });

[elishag80417505]

Thanks so much for the clever quick-fix! I'll see if I can make it work for us (fingers crossed).

[elishag80417505]

That fix worked perfectly - thank you!

It will certainly be helpful while we wait for Adobe to fix this issue.

[jeromiec83223024]

Just looping back on this.  It's not actually a Flash Player bug.  Chrome fails to emit the necessary event when the tab becomes visible in this scenario.

We've opened the following Chrome bug:

https://bugs.chromium.org/p/chromium/issues/detail?id=890008

We do observe that resizing the HTML causes Chrome to restart the rendering pipeline.  The workaround above is your best option until a fix becomes available in Chrome.