1624389 - Momentum scrolling with CTRL key down major bug

Status: UNCONFIRMED

(Core :: DOM: UI Events & Focus Handling, defect, P5)

Description

[zap404]

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

Steps to reproduce:

If the CTRL key is down while momentum scrolling is happening, the page will zoom in or out very rapidly.
Problem is, it is VERY easy to have the CTRL pressed by mistake. Even having it down for an instant leads to disastrous zooming results.
The CTRL key being down was never supposed to affect Momentum scrolling, just arrow key scrolling.

Actual results:

Excessive, insane amount of zooming in/out.
This happens on Linux.

Expected results:

NO zooming in response to momentum scrolling.

Comment 1

[Andrei Purice]

Hey Zap,

I tried reproducing this issue in Linux 16.04 on Nightly 76.0a1 (2020-03-26), beta 75.0b9 and release 74.0 but the zooming was done at a normal rate. Depending on how fast i was scrolling.

Holding the CTRL button and then scrolling with the mousewheel or dragging it up and down in order to scroll the page zooms in at normal speed.

I am not sure if these are the steps you were following but if you could provide more in depth steps or even a video, it could help better.

Comment 2

[zap404]

Hi,

The problem occurs in two apps that supports CTRL with two-finger up/down scrolling to change the zoom factor, namely Firefox and Thunderbird.

The defect happens like this:

1. Use two fingers to scroll up or down in some web page using momentum.
2. When motion comes to a stop, immediately press and hold CTRL.
3. You will see that even though motion has stopped, the zoom-with-CTRL effect will happen until the text becomes either very large or very small.

Comment 3

[BugBot [:suhaib / :marco]]

Bugbug thinks this bug should belong to this component, but please revert this change in case of error.