[OPEN] [#1445] [4.2.0] Strange issue with Firefox 52 (UI freezes on some PCs also on Ext.Net examples...)

[adrianot]

We've experienced many times a strange issue with Firefox. Basically the app renders correctly, but mouse clicks DOES NOT WORK. The Keyboard seems to be working fine, ... but other interactions are "filtered" somehow.

No errors appear on the console, ... and since the issue is not strange enough the issue is present ONLY on certain computers (not all) with the same version.

We've seen that going to this link could help mitigating the issue but only for a short time,...
https://support.mozilla.org/t5/Proce...lems/ta-p/1032

...but in a few days/weeks the issue comes back again and we're forced to reset again Firefox settings.

The behavior can be reproduced on https://examples3.ext.net too!

Is there any known issue with Firefox like this?
Thank you for a feedback,
Cheers

[fabricio.murta]

Hello @adrianot!

Yours the first report on these issues. Same version, different computers don't break? Seems an extensions or plug-ins issue. Something like that may be installed on the affected computers and triggering the error.

Is it definitive? You can't interact with anything in Ext.NET pages? Or need to work on it a while before it stops responding mouse events? The random nature of the issue would make it rather difficult to pinpoint.

Would safe mode help on the affected systems?

[adrianot]

Hi Fabricio, yes, it looks like this ExtJS topic describes the issue:
https://www.sencha.com/forum/showthr...-are-supported

https://bugzilla.mozilla.org/show_bug.cgi?id=1321758

What do you think?
Thank you!

[fabricio.murta]

Yes! That's most definitely it! We are going to log it in our issues tracker too... Maybe something that forces isWebkit to be true on firefox 52 might mend the issue!

But I upgraded Firefox to 52 here and the issue does not trigger... I get Ext.IsWebKit as false as stated in the Sencha thread, yet the examples works just fine. Did you find a definitive way to have Firefox 52 break? It seems just upgrading Firefox to 52 is not enough, there is something else that triggers and disables the mouse events handling.

I have checked this comment which suggests how to fix... But I have the condition it says (dom.w3c_pointer_events.enabled = 2), yet firefox here works very well with Ext.NET. Any interaction like button clicks in this example should not work, right?

It is not a question "is the problem there?", the question is "how to deterministically make firefox break with Ext.NET?"

Without reproducing the issue our side we are helpless to suggest a workaround.

[fabricio.murta]

We have just logged issue #1445 to track this problem. If you have any hint on how to make devices that don't reproduce the issue actually reproduce it, let us know the steps to enable it so we can try an Ext.NET-side fix for this issue, at least for the time being.

For now, I'm afraid the fix would be to disable w3c_touch_events on firefox as instructed in this mozilla comment.

[fabricio.murta]

Can you reproduce the issue on this example:

- Ext.NET 3 - buttons overview

But this one works fine for you?

- Ext.NET 4 - buttons overview