257519 - Backspace at the beginning of a paragraph creates an EMPTY tag

Status: VERIFIED DUPLICATE of bug 244392

(Core :: DOM: Editor, defect)

Description

[Mihai Bazon]

User-Agent:       Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.2) Gecko/20040810 Debian/1.7.2-2
Build Identifier: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.2) Gecko/20040810 Debian/1.7.2-2

Pressing Backspace when the caret is at the start of a paragraph (or probably
any block-level node) makes the editor create an empty tag!  That is, the HTML
code will look like: <>foo</>.  Sometimes (can't give exact steps yet) the
browser crashes few operations thereafter.

Reproducible: Always
Steps to Reproduce:
1. Go to the given URL ( http://www.dynarch.com/htmlarea/examples/core.html )

2. Press CTRL-A (select all text) then DEL.  Then switch to CODE mode (press the
"<>" button in the toolbar).  Enter the following HTML:

<p>foo</p>
<p>bar</p>

3. Switch back to WYSIWYG mode (press "<>" again).  Then place the caret in the
second paragraph, before letter "b", and hit BACKSPACE.

Actual Results:  
The browser will remove both paragraph tags and show the following text (in
WYSIWYG mode):

foo
bar

If you hit the mode button again ("<>" in the toolbar) the HTML code will look
like this:

<>foo<br />bar</>

As you can see, the browser removes both paragraph tags and creates an empty
tag.  I suspected an error in my code but can't find any :-\  I added an
alert("|" + range.startContainer.parentNode.tagName + "|") in JS and the result
was "||", indicating that indeed we have an ELEMENT node with no tag!

Expected Results:  
Pressing BACKSPACE should remove the second paragraph and append its content to
the first paragraph, resulting in the following code:

<p>foo|bar</p>

where "|" indicates the caret position.

Tested this with FireFox 0.9.3 for Linux, Mozilla 1.7.2 for Linux and FireFox
0.9 for Windows (under XP).

I am thinking to fix this directly in JS by intercepting BACKSPACE, but I'm sure
the problem lies in the Midas code and should be fixed there; also, if I
workaround it from JS I'll invalidate the Undo queue (but I guess that's
"alright" since I break it in multiple places anyway..).

Comment 1

[Mihai Bazon]

Oops, same thing happens when you press DEL at the end of the first paragraph :-/

Comment 2

[Asaf Romano (gone)]

*** This bug has been marked as a duplicate of 244392 ***