1503412 - PDF viewer zooms in unexpectedly when switching tabs using keyboard shortcuts

Status: RESOLVED FIXED

(Firefox :: PDF Viewer, defect, P3)

Description

[siddharth.mahen]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:63.0) Gecko/20100101 Firefox/63.0

Steps to reproduce:

This bug occurs sporadically when many PDFs are open at once. I have not been able to reproduce it systematically.

The general idea is to keep several PDFs open in various tabs, and switch between them using the cmd-alt-(right/left arrow key) shortcut. Eventually, when switching to a particular PDF file, it will begin zooming in.


Actual results:

When switching between tabs displaying PDF documents using the cmd-alt-(right/left arrow key) shortcuts, the PDF documents occasionally begin to zoom in.


Expected results:

Switching tabs using the key board shortcuts should not cause PDF documents to zoom in.

Comment 1

[Brendan Dahl [:bdahl]]

Are you also scrolling while switching tabs? Ctrl+scrolling will zoom in/out.

Comment 2

[siddharth.mahen]

> Are you also scrolling while switching tabs? Ctrl+scrolling will zoom in/out.

This helped me figure out the problem.

The bug above can be replicated as follows: Start scrolling upwards/downwards on one tab, and then quickly switch to an adjacent tab that is displaying a PDF (switch using the keyboard shortcuts). 

It looks like the "scroll momentum" carries over into the PDF and "becomes" a zoom.

Comment 3

[siddharth.mahen]

I'm testing this on a Macbook Pro. I initiated the scroll by swiping two fingers up/down on the trackpad.

Comment 4

[Brendan Dahl [:bdahl]]

Can you reproduce with regular web pages or is it only the PDF viewer?

Comment 5

[siddharth.mahen]

> Can you reproduce with regular web pages or is it only the PDF viewer?

I cannot.

Comment 6

[siddharth.mahen]

To clarify, I cannot reproduce this with regular webpages; the bug only occurs in the PDF viewer.

Comment 7

[siddharth.mahen]

One more time: I have attempted to reproduce the bug using regular webpages and have not succeeded. Sorry for the ambiguity ^^

Comment 8

[Jonas Jenwald [:Snuffleupagus]]

There's a chance that these problems are a lot less frequent, or even fixed, in Firefox 66 (which was released yesterday).

Can you please try this again, using Firefox 66, and report back if there's any improvements here?

Comment 9

[siddharth.mahen]

From what I've tested so far, I haven't seen this issue crop up in Firefox 66.

Comment 10

[siddharth.mahen]

However, the following strange behaviour still occurs: when scrolling up/down on a PDF document and quickly switching to another tab (not containing a PDF), the page continues to scroll up/down.

Comment 11

[Jonas Jenwald [:Snuffleupagus]]

(In reply to siddharth.mahen from comment #9)

From what I've tested so far, I haven't seen this issue crop up in Firefox 66.

Great; I'm going to mark this as fixed then, thanks for checking :-)

(In reply to siddharth.mahen from comment #10)

However, the following strange behaviour still occurs: when scrolling up/down on a PDF document and quickly switching to another tab (not containing a PDF), the page continues to scroll up/down.

Which document does "the page continues to scroll up/down" refer to here, the original PDF document or the other tab?

Anyway, to me that sounds like a different bug. Can you please file a new bug, with steps to reproduce?