629362 - Two finger scrolling on Mac followed control results in rapid change of webpage font size

Status: RESOLVED DUPLICATE of bug 574663

(Firefox :: Keyboard Navigation, defect)

Description

[peter a]

User-Agent:       Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:1.9.2.13) Gecko/20101203 Firefox/3.6.13
Build Identifier: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:1.9.2.13) Gecko/20101203 Firefox/3.6.13

On a Macbook pro laptop, when scrolling through and switching multiple tabbed pages in order to quickly review the validity of something like search results, I stumbled upon what seems to be an unexpected behavior where the font size of the current webpage changes according to the direction of the last performed two-finger scroll. 

The problem is most prevalent when scrolling up/down on one page (i.e. quickly review its content) and then having to use Control-TAB to switch to the next/previous page quickly where the behavior carries over to the next/previous tab.

Reproducible: Always

Steps to Reproduce:

1. Find any page.
2. Using two fingers on a Macbook mouse pad, scroll down on the page (the side scrollbar does not need to be present) 
3. Immediately afterwards (i.e. 1/2 sec, but not while the mouse pad is still touched), press the control key
4. The font size of the current webpage DECREASES.
5. Using two fingers scroll upwards (the side scrollbar does not need to be present) 
6. Immediately afterwards, press the control key
7. The font size of the webpage INCREASES
8. Scrolling and not pressing Control immediately afterwards results in no change of font size
Actual Results:  
Font size of the webpage increases and decreases.  See #4 and #7 in Steps to Reproduce

Expected Results:  
Nothing

Vanilla Firefox installation.

Comment 1

[Markus Stange [:mstange]]

This will be fixed in Firefox 4.