Element zapper does not function on Ublock origin, Firefox mobile.

[infradragon]

Prerequisites

• I verified that this is not a filter list issue. Report any issues with filter lists or broken website functionality in the uAssets issue tracker.
• This is NOT a YouTube, Facebook or Twitch report. These sites MUST be reported by clicking their respective links.
• This is not a support issue or a question. For support, questions, or help, visit /r/uBlockOrigin.
• I performed a cursory search of the issue tracker to avoid opening a duplicate issue.
• The issue is not present after disabling uBO in the browser.
• I checked the documentation to understand that the issue I am reporting is not normal behavior.

I tried to reproduce the issue when...

• uBO is the only extension.
• uBO uses default lists and settings.
• using a new, unmodified browser profile.

Description

The element zapper does not zap elements. When you open the uBlock Origin dialog from the extensions menu, and select the element zapper, it returns you to the previous webpage in element zapper as expected. However, while clicking on an element selects it, and clicking it again removes it, there is no way to exit the element zapper mode. You are permanently stuck removing elements until the page is reloaded, in which case all of the elements will come back again (expected behavior, but causes this to be a bug entirely preventing use of the element zapper.)

I have tested this on both Firefox nightly (128.0a1) and stable. A friend of mine has also tested it on his smartphone (unknown model and firefox version.)
A possible fix is to add a dialog at the bottom of the screen with a back or exit button, to allow the user to exit the element zapper mode.

A cleaner but likely impossible to implement fix would be to reuse android's back button to exit the element zapper.

A specific URL where the issue occurs.

https://thebestmotherfucking.website/

Steps to Reproduce

Install and launch Firefox mobile

Expected behavior

The element zapper works in a way that allows the user to exit the element zapping mode.

Actual behavior

The user becomes stuck in the element zapper until the page is reloaded.

uBO version

1.58.0

Browser name and version

Firefox Nightly 128.0a1 (Mobile)

Operating System and version

Android 14 aarch64 (Linux 4.19.278-g7b0944645172-ab1081281) Google Pixel 5, Stock ROM

[infradragon]

I just found out that there is an actual way to exit the element zapper, but it is not intuitive.
https://github.com/uBlockOrigin/uBlock-issues/wiki/Element-zapper#on-touch-screen-devices
I reported this because multiple people thought that there was an issue with the element zapper, me included...

[garry-ut99]

Duplicate of:

• element zapping mode does not work in mobile firefox #1968
  Describe the issue: Whoever thought "swiping right twice" is a good method of closing element zapper, should swap his head with his arse back - the previous swap did not work.

and:

• How to exit element zapper mode in mobile phone #1815
  This is an astonishingly bad mechanism. Swipes arent reliable. There really ought to be a simpler way to handle this. (press and hold anywhere?)

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infradragon: I reported this because multiple people thought that there was an issue with the element zapper, me included...

I'm a little ashamed to admit it, but since it's so funny, I will share: in the past when I used Zapper on Mobile for the first time I also experienced the same thing ("being trapped"), then I read Wiki and found out about "swipe right", since then I have no issue with it anymore because once I learned it for the first time I do remember it always and it's very good and easy way. But I must admit that users who use Zapper on Mobile for the first time might get trapped and might complain. Anyway I'm not sure if it's something that ubo is guilty of, as on the other hand it might be considered also as users's fault of not thinking about swiping, as swiping is a common way of working on Mobile.

[u-RraaLL]

A possible fix is to add a dialog at the bottom of the screen with a back or exit button, to allow the user to exit the element zapper mode.

Yes, something like the minimized picker bar could be helpful.

I've also seen a number of people over the years ask for the persistent zapper mode on desktop (not being aware of achieving this with the [Del] shortcut). With the floating bar (or just a button) uBO could have consistent behavior in both places.

when I used Zapper on Mobile for the first time I also experienced the same thing

You're not the only one. I rarely ever use zapper myself. I'm quite sure I've encountered the same thing a few years back whilst investigating some reddit report. My first thought being maybe a bug caused by the website's CSS.

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@gorhill I'm leaving this open since the suggested solution is a valid one (IMO) and you've asked for suggestions in the older issue:

Feel free to suggest what would work better on a mobile's touch screen.

[krystian3w]

Del is still bugged e.g. if tab in browser lost focus - workaround: once remove with shift + mouse button and later by Del until lost focus (glitch).

[observeroftime01]

It would be wicked cool if there could be a small message popping up the first time a user uses the element zapper mode running on a mobile browser, pointing out those basic controls. Even just a one-time message with these bullet points would probably be sufficient:

• Tap once to select the element.
• Tap the highlighted element to remove it.
• Swipe right to remove the incorrect highlighting.
• Swipe right to exit element zapper mode.

I have to admit I never used the zapper mode on mobile, because I could never figure out how to make it work (navigation-wise, how to get out of it and save my changes), and wrote it off as "probably only works on desktops", and never bothered to look into it any further.

[Erwan62]

Thanks for these tips
I, too, found myself stupidly stuck.
Not being at all intuitive, information is really needed in the app!