775440 - CSS positioning buggy, fixes after selecting with Firebug

Status: UNCONFIRMED

(Core :: General, defect)

Description

[Marcos]

Attachment: website.rar

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:15.0) Gecko/20100101 Firefox/15.0
Build ID: 20120717110313

Steps to reproduce:

So I've been placing error messages behind the fitting texts. To let them overflow the layout, I positioned them absolute based on the relative positioned tag surrounding it.


Actual results:

Comparing this over different browsers, I've seen little differences in the positioning (which is not a major problem), one thing that really wondered me though was that the positioning changed when I selected the error text with Firebug, it suddenly moves a few pixels up like it recalculates the positioning.
I can repeat this every time and it works. To make a comparison, you could pick Google Chrome, where the text positions correctly from the beginning, while in Firefox it needs a Firebug selection.


Expected results:

While I don't complain about the pixel difference, I think this can be considered a bug, as the behavior changes when Firebug comes in play.

I've attached the website in an archive, the red texts are the error messages, select them with Firebug and you understand what I mean.

Comment 1

[j.j.]

Please try to create reduced HTML file and attatch it, thanks!
See  https://developer.mozilla.org/en/Reducing_testcases

Comment 2

[Marcos]

Attachment: Website

Comment 3

[Marcos]

(In reply to j.j. (inactive in 2012) from comment #1)
> Please try to create reduced HTML file and attatch it, thanks!
> See  https://developer.mozilla.org/en/Reducing_testcases

OK, I've slimmed down the website, only a few lines now.

Meanwhile, I understood WHEN the error is happening:

The website has to be long enough to activate the scrollbar (that's why I made the textarea that long).
Now if you change the textarea heght to something really short, the site will be short enough to not show the scrollbar anymore. At the same moment, the error-texts will move up a few pixels, so this probably has something to do with the scrollbar.