422319 - Certain zoomed pages resize when DHTML iframes are introduced

Status: RESOLVED FIXED

(Firefox :: General, defect)

Description

[karl]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.8.1.12) Gecko/20080201 Firefox/2.0.0.12
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 6.0; en-GB; rv:1.9b4) Gecko/2008030714 Firefox/3.0b4

If a zoomed page (say http://google.com/) is loaded into a background tab it gains the zoom for that domain. If a dhtml iframe is created on that background page the page decreases to normal zoom state leaving large black borders between it and the browser scroll bars. Browser scroll bars are reproduced inside the viewpane (so there are then 4 scroll bars), and generally page looks terrible.



Reproducible: Always

Steps to Reproduce:
This is probably reproducible in other ways, but this (for me) is easiest.
NOTE: Firefox 3 only. this is not reproducible in FF2
1. Download and install the Interclue add-on (https://addons.mozilla.org/en-US/firefox/addon/4999). Please note: I do not believe this bug is due to the Interclue add-on, it's just an easy way to reproduce it (you'll have to set "extensions.checkCompatibility = false" in about:config). 
2. Restart browser
3. Navigate to a domain (eg http://google.com/)
4. Zoom the page (hit [ctrl]++) 
5. Use Interclue to preview a link on this page
  5a. hover mouse over a link until an icon appears next to it.
  5b. hover mouse over the icon until the iframe appears.
  (this is whats supposed to happen) 
6. Open a new tab, and select it
7. Navigate new tab to same domain (http://google.com/) (should appear zoomed)
8. Use Interclue to preview a link on this page
  8a. Hover mouse over a link (eg "about google") until the icon appears next to the link
  8b. Hover over icon to show the iframe.
9. Iframe is displayed and page re-zooms, corrupting page entirely.

NOTE: this ONLY happens in NEW TABS where the zoom is automatically applied. It does not happen if the user presses the [ctrl++] keys to set the zoom level for a page.

Actual Results:  
Page is shrunk to "normal" zoom level when iframe is built.

Expected Results:  
Page should stay at given zoom level (iframe should also be zoomed)

I've tested this in 3.0b3, 3.0b4, and minefield. 

AGAIN: this ONLY happens in NEW TABS where the zoom is automatically applied. It does not happen if the user presses the [ctrl++] keys to set the zoom level for a particular tab.


I've run a debugger over the Interclue add-on and the error occurs when the line

iframe.style.display = "block";

is evaluated. I don't think this is the add-ons fault, but I could be wrong.
I've tried to re-create this bug using a normal html page with javascript to generate iframes, but no luck.

Comment 1

[Mike Beltzner [:beltzner, not reading bugmail]]

Not blocking until we can confirm.

Myk: can you take a peek?

Comment 3

[karl]

The fix for 433727 also fixes this bug.