1206382 - preventDefault against dynamic toolbar has no effect

Status: RESOLVED DUPLICATE of bug 1044370

(Firefox for Android Graveyard :: General, defect)

Description

[juwagn]

User Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:40.0) Gecko/20100101 Firefox/40.0
Build ID: 20150826023504

Steps to reproduce:

The background div element overflows visible area, so it is scrollable down and up.
It has attached a "absolute" positioned div element that is moved by JavaScript with 
"touchmove" event. 


Actual results:

When the touchmove event is fired, the JavaScript calls on this event event.preventDefault();
event.stopPropagation();
return flase;
the touched div element gets moved by attaching positions extracted from touchmove event.
Now the issue, when moving finger down or up, the dynamic toolbar is moving together with background div element so creating undesired effect.


Expected results:

When moving finger over a element with fired event.preventDefault(); the dynamic toolbar and background body should stay at same position.

Actually the worse scenario workaround is to set in about:config
browser.chrome.dynamictoolbar = false
which causes the dinaymic toolbar to be disabled completely, that is not desired action and can not be recommended to users, even if it helps to disable the undesired effect.

Comment 1

[juwagn]

Seems to be same issue as 
1044370

Comment 2

[juwagn]

From what I have read, actual discussion why it can not be fixed is based on fear of FF mobile developers, this option could be used to catch user in situation where the user could not be able to show up the toolbar again once it was hidden, so trapping the user on same page.

Possible proposal and easiest solution, when event.touches.length < 2 then preventDefault should be respected and dynamic toolbar should stay at same position, but as soon user touches two fingers the browser should forward the event from primary touch to the dynamic toolbar despite of prventdefault behaviour.
In such case the malicious code would not get a chance to trap the user in worse scenario sitiation and every one would be happy, since to 99% only one finger gestures are actually suffering due this FF issue with dynamic toolbar.

Comment 4

[Kevin Brosnan [Ex-Mozilla]]

Using the fullscreen API is an option. https://fullscreen.spec.whatwg.org/

Comment 5

[juwagn]

Well,
browser.chrome.dynamictoolbar = false is better option
but no one of them fix the issue.