1595394 - Detect mouse scrolling outside the page (but within the window) while privacy.resistFingerprinting.letterboxing is set to true

Status: UNCONFIRMED

(Core :: Window Management, defect, P5)

Description

[antistress]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Firefox/68.0

Steps to reproduce:

(With Firefox 70 on my Debian GNOME system)
Set privacy.resistFingerprinting.letterboxing to true
While Firefox is displayed in full screen, try to scroll with mouse wheel while the pointer sit at the left or at the right side of the screen (as you may do by reflex)

Actual results:

Nothing happens since the pointer is outside the web page (which is the consequence of letterboxing) even if it's inside Firefox window

Expected results:

Firefox should be smart enough to forgive the user and decide to scroll the page nevertheless

Comment 1

[antistress]

Attachment: mouse_scroll zones to take into account in letterboxing mode

Comment 2

[Thorin [:thorin]]

Wouldn't this just lead to possible entropy with coordinates, mouse events .. and add way too much complexity?

Comment 3

[Tom Ritter [:tjr]]

(In reply to Simon Mainey from comment #2)

Wouldn't this just lead to possible entropy with coordinates, mouse events .. and add way too much complexity?

You can trigger scrolls without mouse events or coordinates: e.g. by using the up/down arrows on the keyboard.

That said, as letterboxing is currently implemented I'm not sure how we would actually fix this bug; but I'm not opposed to keeping it on the list.

Comment 4

[sworddragon2]

Personally I would prefer if the website does not scroll if I scroll on a chrome area but I can think of why users want this feature: After enabling letterboxing I did also scroll by accident on the letterboxed chrome area and got confused for a second why the website does not scroll. The main issue is here that the most websites do use a very light background very similar to Firefox's default theme/current letterboxed chrome area and that a separation line is needed to distinguish between the letterboxed chrome area and the content window. Bug #1594455 should handle this and I made also a comment for the separation line.