1252521 - [UX] Ctrl+Scrollwheel works intermittently & may zoom into off-page area, in Print Preview. (whereas Ctrl +/- does nothing)

Status: RESOLVED DUPLICATE of bug 236594

(Core :: Print Preview, defect)

Description

[Daniel Holbert [:dholbert]]

[Note: this is windows/linux-only -- we don't provide Print Preview UI on mac]

STR:
 0. Have a mouse with a scrollwheel.
 1. Print-preview some page, e.g. this bug page here.
 2. Hold down your ctrl key and move your scrollwheel up and down.
 3. (If nothing happens, repeat step 2 while moving your cursor around.)
 4. Try using the keyboard full-page-zoom controls -- Ctrl +, Ctrl -, Ctrl 0,

EXPECTED RESULTS:
 * Keyboard zoom controls and mouse zoom controls should work/not-work consistently. (So both should work, or both should have no effect)
 * If both work: they should zoom in with the page centered in the viewport.

ACTUAL RESULTS:
 * Keyboard zoom controls have no effect.
 * Ctrl + Scrollwheel seems to zoom in/out, but it does so inconsistently. (Seems to work or not-work depending on where my cursor is pointing.)
 * When the zoom happens, it seems to be centered on an arbitrary point (sometimes somewhere off the page).

Comment 1

[Daniel Holbert [:dholbert]]

Screencast of bug, with current Nightly & fresh profile:
 https://www.youtube.com/watch?v=1-xjnf3pklA

Comment 2

[Daniel Holbert [:dholbert]]

In the screencast, I'm simply doing Ctrl+mousewheel to zoom.

It's especially broken towards the end -- https://www.youtube.com/watch?v=1-xjnf3pklA&t=0m13s

I suspect we don't intend for this zooming to have any effect, and it only "kinda works" by accident. However, we might want it to have an effect (and make it work reliably) as a way of addressing bug 1249846.

Comment 3

[Daniel Holbert [:dholbert]]

Attachment: screenshot 1: page mostly offscreen

Here's a screenshot, showing that the print-previewed page can end up mostly-offscreen after zooming in & out for a bit with Ctrl+mousewheel.

Comment 4

[Daniel Holbert [:dholbert]]

This is not a (recent) regression, BTW -- I can reproduce in current release (Firefox 44.0.2) as well as Nightly 47.0a1 (2016-02-29)

Comment 5

[Daniel Holbert [:dholbert]]

(And I'm using Ubuntu Linux 15.10 64-bit, though I'll bet this reproduces on Windows as well.)

Comment 6

[Jonathan Watt [:jwatt]]

Should this be duped (or wrapped up with) bug 236594?

Comment 7

[Jonathan Watt [:jwatt]]

Hmm, or bug 127909.

Comment 8

[Daniel Holbert [:dholbert]]

Yeah -- as-filed, this seems to be a direct dupe of bug 236594. (Though, indeed, the eventual fix might involve disabling pointer interaction via bug 127909 or similar.)