277480 - XHTML page on web server reported as content-type text/html instead of application/xhtml+xml, causes vertical misalignment of title bar.

Status: RESOLVED INVALID

(Core :: Layout: Block and Inline, defect)

Description

[Andrew Arnott]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8a6) Gecko/20050107 Firefox/1.0+
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8a6) Gecko/20050107 Firefox/1.0+

On the very top blue bar of the page, the logo in the top left corner that says
"BYU" has "BRIGHAM YOUNG UNIVERSITY" directly to its right.  In Internet
Explorer, the text in the logo and the spelled out title are aligned
(vertically).  In FireFox, they are not.  

When the web page and dependency CSS and image files are downloaded to the hard
drive and viewed locally, the alignment is correct!  

Reproducible: Always

Steps to Reproduce:
I discovered that the cause of this problem is that the web server's
content-type header is set to text/html instead of the more appropriate
application/xhtml+xml.  When I moved the pages to a server properly configured,
the misalignment disappeared!  
Actual Results:  
Firefox is deciding alignment based on which content-type header is specified
(of text/html or application/xhtml+xml).  This seems wrong.

Expected Results:  
That although an XHTML document is represented to the browser as text/html, the
browser should still correctly render it without alignment problems.

I know very little about Gecko, so I hope this is a helpful bug report.  I'm
sorry if it's in the wrong category.  Please contact me if you have further
questions.

Comment 1

[Andrew Arnott]

Attachment: Highlights the misalignment of text

Comment 2

[Andrew Arnott]

Attachment: This shows how the alignment automatically corrects itself when the same page is loaded from the hard drive

Comment 3

[Mats Palmgren (inactive)]

Attachment: Testcase, application/xhtml+xml

Comment 4

[Mats Palmgren (inactive)]

Attachment: Testcase, text/html (same file)

Comment 5

[Mats Palmgren (inactive)]

This is probably due to our "Almost Standards" mode, see the note on
line-height in bug 153032 comment 19.

(Note that "Page Info" lies about the mode - it can't tell "Full Standards"
from "Almost Standards" mode, bug 154359)

Comment 6

[Boris Zbarsky [:bzbarsky]]

Yeah, that would cause the observed behavior difference.  So this looks invalid.

Comment 7

[Daniel.S]

Removing the doctype of the testcase (to trigger quirks mode) makes the code behave just like it does in Almost Standards Mode (which is intentional).
This is documented under http://developer.mozilla.org/en/docs/Mozilla_Quirks_Mode_Behavior#Block_and_Inline_layout

-> Invalid.