426039 - White lines on frame border which multiply when zoomed in

Status: UNCONFIRMED

(Core :: Layout: Images, Video, and HTML Frames, defect)

Description

[Duncan Loveday]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9pre) Gecko/2008032805 Minefield/3.0pre
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9pre) Gecko/2008032805 Minefield/3.0pre

A frameset with frameborder="15" is rendered with a spurious white line on the frame border. When zooming in using ctrl + this white line turns into 2 white lines then 4 then 8, 16 etc.

There's also a black line at the top of the lower frame although this doesn't multiply when zooming.

Reproducible: Always

Steps to Reproduce:
1. Open the attached test case
2. Press ctrl +
3.
Actual Results:  
In step 1 a single horizontal white line is present near the top of the frame border and a single horizontal black line is present at the top of the lower frame.

In step 2 the number of white lines double with every press of ctrl +

Expected Results:  
No lines should be present

Comment 1

[Duncan Loveday]

Attachment: test case

Comment 2

[Duncan Loveday]

The single white and single black line have been present ever since FF 2 and might be intentional, i.e. part of the border style.

In which case the only issue is the fact that the white lines multiply when zooming in. This appears to have been the case ever since the zoom facility was introduced in http://ftp.mozilla.org/pub/mozilla.org/firefox/nightly/2007/10/2007-10-26-05-trunk/firefox-3.0a9pre.en-US.win32.installer.exe.

It also seems to affect normal size frame borders, not just wider than normal ones.