Last Comment Bug 93592 - floats can be overwritten
: floats can be overwritten
Status: NEW
: css1, testcase
Product: Core
Classification: Components
Component: Layout: Floats (show other bugs)
: Trunk
: All All
P3 normal with 3 votes (vote)
: Future
Assigned To: Nobody; OK to take it and work on it
: Jet Villegas (:jet)
Depends on: 25888
Blocks: 345369 css2.1-tests 228588
  Show dependency treegraph
Reported: 2001-08-03 20:02 PDT by Brian Clark
Modified: 2016-06-27 21:17 PDT (History)
6 users (show)
See Also:
Crash Signature:
QA Whiteboard:
Iteration: ---
Points: ---
Has Regression Range: ---
Has STR: ---

screenshot of the w3c test case (138.73 KB, image/jpeg)
2001-08-04 10:29 PDT, Brian Clark
no flags Details
simplified testcase (4.44 KB, text/html)
2001-12-03 02:25 PST, Pierre Saslawsky
no flags Details
Shows text overlapping a floated text element. (4.17 KB, image/gif)
2002-01-18 07:54 PST, Eric A. Meyer (dead account)
no flags Details
Another testcase (1.00 KB, text/html)
2002-09-21 15:40 PDT, Mats Palmgren (:mats)
no flags Details

Description User image Brian Clark 2001-08-03 20:02:45 PDT
From Bugzilla Helper:
User-Agent: Mozilla/5.0 (Macintosh; U; PPC; en-US; rv:0.9.3) Gecko/20010802
BuildID:    2001080214

Mozilla 0.9.3 for MacOS 9.1 fails a portion of the W3C's CSS1 Test Suite: 4.1.4
Floating Elements.

Some of the floated elements on the page are overwritten by some of the DIV text.  

Reproducible: Always
Steps to Reproduce:
1.Go to the above web page
2.Load the page
3.Scroll down to see the examples of the floated elements being overwritten by
portions of the DIV text.
Comment 1 User image Mats Palmgren (:mats) 2001-08-04 10:22:25 PDT
WFM, 2001-08-01-03 on Windows 98 SE.
Comment 2 User image Brian Clark 2001-08-04 10:29:17 PDT
Created attachment 44692 [details]
screenshot of the w3c test case
Comment 3 User image Mats Palmgren (:mats) 2001-08-04 11:21:16 PDT
Are you using a "View - Text Size" other than 100% ? I see text overlapping
the floaters if I use 90% or 120% for example.
Comment 4 User image Brian Clark 2001-08-04 11:46:44 PDT
I don't seem to have this "View - Text Size" option in Mozilla 0.9.3 for Mac. 
It should be on the "View" menu at the top of the screen, right?  I would have
to assume that since I don't have it, the text size is hard coded somewhere. 
Comment 5 User image karnaze (gone) 2001-08-06 15:48:02 PDT
Reassigning to attinasi.
Comment 6 User image Jason A. 2001-11-19 00:15:36 PST
behaviour confirmed on win98. DIV text overlaps floating elements' text.

Mozilla/5.0 (Windows; U; Win98; en-US; rv:0.9.6+) Gecko/20011118
Comment 7 User image rubydoo123 2001-11-29 20:57:37 PST
handing over to Pierre for debug
Comment 8 User image Pierre Saslawsky 2001-12-03 02:24:51 PST
Back to Layout.  Changed the summary line from "Mozilla fails a portion of the 
W3C's CSS1 Test Suite: 4.1.4 Floating Elements" to "[FLOAT] floats can be 

I understand it is bad to fail even a part of a testcase from the CSS1 test suite 
but in that case it doesn't seem to be too important.  Look at the attached 
simplified testcase.  The DIV text only overwrites the second float when:
* the two floats don't fit on the same line
* the margin on these floats is very small (either 0 or a few pixels)
Comment 9 User image Pierre Saslawsky 2001-12-03 02:25:43 PST
Created attachment 60142 [details]
simplified testcase
Comment 10 User image Eric A. Meyer (dead account) 2002-01-18 07:51:35 PST
I have another example of this bug, although it takes some work to find it.  The
URL is but the bug
only manifests at certain browser window sizes (and thus certain flow
arrangements).  I'm going to attach a screenshot I took of the problem, so that
hopefully others can reproduce the same bug.  The screenshot was taken in
2002011803/Mac.  (It also shows a different bug that I'm going to be submitting.)

As for this being unimportant, I very much disagree.  If it's possible for
normal-flow text to overwrite floats, then floats become a lot less useful for
advanced page layout.  It also makes me less sanguine about our flow
calculations in general, since it implies that we don't really know where
everything is and so can't figure out when a line should be wrapped.  That
seems, well, bad.
Comment 11 User image Eric A. Meyer (dead account) 2002-01-18 07:54:42 PST
Created attachment 65622 [details]
Shows text overlapping a floated text element.

You can see the words "is 1em" overlapping the borders of a floated text
element.  Other words can be coaxed to overlap the float to varying degrees by
resizing the browser window.
Comment 12 User image Eric A. Meyer (dead account) 2002-01-18 08:07:50 PST
The erroneous white vertical line has been reported in bug 120783.
Comment 13 User image Madhur Bhatia 2002-05-13 18:46:08 PDT
I do not see this problem occuring on win2000.
But I do see it on RedHat Linux 7.3 

Build ID tested on :-
win2000: 2002-05-12-20-XX-PR1
linux 7.3: 2002-05-12-23-XX-PR1
Comment 14 User image Madhur Bhatia 2002-05-14 17:28:39 PDT
also see it on macOS 9.1 
buildID: 2002-05-12-17-XXpr1
Comment 15 User image Mats Palmgren (:mats) 2002-09-21 15:40:07 PDT
Created attachment 100116 [details]
Another testcase
Comment 16 User image Christopher Hoess (gone) 2003-06-08 12:17:52 PDT
Comment 17 User image David Baron :dbaron: ⌚️UTC-8 2003-06-08 13:29:37 PDT
This is another slightly-more-complicated variant of bug 25888 (as is bug 41412).
Comment 18 User image Wayne Mery (:wsmwk, NI for questions) 2006-03-23 10:29:57 PST
still fails Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9a1) Gecko/20060306 Firefox/1.6a1

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