434841 - cursor leaves dirt trail (drawing artifacts) in textarea during pasting

Status: RESOLVED WORKSFORME

(Core :: Web Painting, defect)

Description

[martin]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.9pre) Gecko/2008051906 Minefield/3.0pre
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.9pre) Gecko/2008051906 Minefield/3.0pre

1. Create a really big textarea box (like 75% of screen height and width).
2. Enter the following text into it "a\nb\nc" (where "\n" denotes NEWLINE char).
3. Select both of the empty and the "b" line at once.
4. (Firefox only shows the selection over "b" but we've actually selected the newlines as well; this is all expected).
5. Press CTRL-C and then CTRL-V to duplicate the selection.

Actual results:
At the location where the cursor was originally placed there is a static, non-blinking, ghost cursor (basically a drawing artifact left there due to cursor erasing not working correctly).

Expected results:
FF should insert "\nb\n" without leaving ghost cursor artifact.


This bug consistently repros on Minefield 200805190 running on win2k as well as another machine which has got Ubuntu FF3b5.

Reproducible: Always

Steps to Reproduce:
1.
2.
3.

Comment 1

[martin]

Attachment: this is what the drawing artifact looks like on win32

Comment 2

[martin]

Here is a video showing the bug and how to repro it:
http://files.minimum.se/bug_attachments/ff3/bug_434841_cursor_drawing_dirt/repro_steps.ogg

Go to this URL to repro:
http://da.wikipedia.org/w/index.php?title=Alr%C3%B8&action=edit&oldid=1969018

The select everything below and above the line that starts with [[es:Al... like I'm showing in the video.

Comment 3

[martin]

Regression range is as follows.

Last builds WITHOUT this bug in them:
Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9a2pre) Gecko/20070206 Minefield/3.0a2pre (directory "2007-02-06-04-trunk/")
Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9a2pre) Gecko/20070206 Minefield/3.0a2pre (directory "2007-02-06-11-trunk/")

Earliest builds WITH this bug in them:
Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9a3pre) Gecko/20070207 Minefield/3.0a3pre (directory "2007-02-07-01-trunk/")
Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9a3pre) Gecko/20070207 Minefield/3.0a3pre (directory "2007-02-07-04-trunk/")

Comment 4

[Daniel Holbert [:dholbert]]

Confirmed on Ubuntu 8.04 Linux, both while following the steps in Comment 0 and while repeating the steps shown in the video from Comment 2.

Build ID:
Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9) Gecko/2008051202 Firefox/3.0

One correction to comment 0: 
> 2. Enter the following text into it "a\nb\nc" (where "\n" denotes NEWLINE
> char).
> 3. Select both of the empty and the "b" line at once.

Pretty sure the reporter means a\n\nb\n\nc\n\n, that is:

a

b

c

And I think step 3 means to start the selection at the first blank line (above 'b') and select all the way up until just before the 'c' character.

Here's some more information:
  - The corruption is only visible when I perform the 'paste' while the cursor is in the visible half of its blinking state.
  - Corruption only happens when there's no vertical scrollbar present on the textbox.
  - Any existing corruption disappears when I move my mouse pointer from being over the textbox to being away from the text box. (or vice versa)

Comment 5

[Daniel Holbert [:dholbert]]

(In reply to comment #3)
> Regression range is as follows.
> 
> Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9a2pre) Gecko/20070206
> Minefield/3.0a2pre (directory "2007-02-06-11-trunk/")
> 
> Earliest builds WITH this bug in them:
> Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9a3pre) Gecko/20070207
> Minefield/3.0a3pre (directory "2007-02-07-01-trunk/")

That gives this Bonsai link:
http://bonsai.mozilla.org/cvsquery.cgi?treeid=default&module=all&branch=HEAD&branchtype=match&dir=&file=&filetype=match&who=&whotype=match&sortby=Date&hours=2&date=explicit&mindate=2007-02-06++10%3A30%3A00&maxdate=2007-02-07+01%3A30%3A00&cvsroot=%2Fcvsroot

which points to bug 177805

Comment 6

[Daniel Holbert [:dholbert]]

(In reply to comment #5)
> (In reply to comment #3)
> > Regression range is as follows.

I just tried out the two nightlies mentioned in comment 5 myself, and I can confirm that regression range.

So, yeah, bug 177805

Comment 7

[Daniel Holbert [:dholbert]]

The corruption only happens at certain zoom ratios, for certain testcases.

Here's the behavior of my FF3 rc1 on Linux, on the Wikipedia URL:
(zoomlevel : bug/no-bug)
   0: bug
  +1: bug
  +2: bug
  +3: no bug
  +4: bug
  +5: no bug
  +6: bug
  +7: bug
  +8: bug

Comment 8

[Daniel Holbert [:dholbert]]

Attachment: (testcase 1 with incorrect directions)

This testcase reproduces the bug for me in FF3rc1 when fully zoomed in. (though it doesn't reproduce at the default zoom-level.)

Comment 9

[Daniel Holbert [:dholbert]]

Attachment: testcase 1

(oops -- I left out the word "copy" in the instructions on the previous version of testcase 1)

Comment 10

[Emil Pasca [:emilpasca]]

User Agent: Mozilla/5.0 (Windows NT 5.2; WOW64; rv:49.0) Gecko/20100101 Firefox/49.0

This issue has been tested on an older version of Firefox (3.0) on Win XP x64, and it was reproducible.
After opening testcase 1, zooming 8 times and then selecting all and copy pasting the selected text the drawing artifact appears as in the attached screenshot.
However this issue has been tested on Win 10 x64, Win XP x64, with the latest Firefox release (46.0.1) and with the latest Nightly(49.0a1-20160531030258) and it is no longer reproducible.

Considering this I will mark this issue as Resolved-WORKSFORME. If anyone still encounters this issue feel free to reopen it providing more details or file a new one.