1934393 - pdf scrolling does not work reliably when desktop site is enabled

Status: NEW

(GeckoView :: PDF Viewer, defect)

Description

[Jonas]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:134.0) Gecko/20100101 Firefox/134.0

Steps to reproduce:

I opened a PDF in landscape orientation my tablet.
The same behaviour exists with a touchpad too (from my Samsung Keyboard Cover).
Tested in Firefox Beta (134.0b2) and Firefox Nightly (135.0a1)

Actual results:

Scrolling mostly works on the left side of the screen (not 100% reliably) and does completely not work on the right side (dead zone).
I'll try to attach a screen recording.

I measured where the dead zone begins, and it's exactly the height of my tablet (as in the width of my tablet in portrait orientation), which makes me believe the scrolling area is correct in the portrait orientation as it correctly uses the width of my tablet, but the scrolling area is incorrect in landscape as it uses the wrong widht in landscape orientation.

Expected results:

The scrolling should work on the whole screen in landscape orientation

Comment 1

[Jonas]

Attachment: in this video it didn't work at all

Comment 2

[Jonas]

Attachment: Here you can see how it works mostly on the left side, but not on the right side (unless the page is still in motion)

Comment 3

[Jonas]

Just realized the same issue happens with the pdf.js demo https://mozilla.github.io/pdf.js/web/viewer.html but only on Firefox Fenix, so I'm not sure if this is a pdf.js issue or a Fenix issue. Could this also be a WebCompat issue?

Comment 4

[Nicholas Poon [:Nick]]

Thanks for reporting this bug. Is this a website PDF that you're opening or a local PDF? Also, can you provide us with your device and its Android version please?

Comment 5

[Jonas]

In the screen recordings I opened a PDF from a website, but the same behaviour exists if I'm opening a local pdf (content://media/external/file/....).

An I'm on Android version 14, and the device is the Samsung Galaxy Tab S10 Ultra.

Let me know if I can provide some more information like logs or something like that!

Comment 6

[Nicholas Poon [:Nick]]

Ah I see. Thanks for providing us with this additional information and the videos. One more thing - it seems that you may have desktop mode toggled on - this is the new default for tablets but was recently temporarily disabled due to some regressions. Can you try toggling it off and seeing if you can still reproduce the issue?

Comment 7

[Jonas]

Yes this seems to be the issue, without desktop mode it works fine, and with desktop mode the bug appears.
Though opening PDFs without desktop mode makes them very small at first, so one needs to zoom in everytime when opening a PDF without desktop mode, would be great if this could be fixed in the desktop mode! Otherwise I at least know how to mitigate this issue until this has been fixed, thanks!

Comment 8

[Nicholas Poon [:Nick]]

Thanks for confirming, moving this back to Fenix :: General and adding this to the Desktop mode by default meta, as this may be a blocker for the feature to be re-enabled

Comment 9

[Nicholas Poon [:Nick]]

Confirming this as I was able to reproduce it on my emulator tablet.

Comment 10

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Fenix::Media' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.