282638 - Undo coalesces too many edit actions

Status: NEW

(Core :: DOM: Editor, defect, P5)

Description

[Davor Cubranic]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.5) Gecko/20041107 Firefox/1.0
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.5) Gecko/20041107 Firefox/1.0

Undo seems to treat multiple consecutive editing actions (such as
Control-Backspace to delete a word) as a single one. That is rarely the case.
For example, when I type a few words, change my mind and delete the last few,
but then go one too far, selecting Undo will restore the whole sentence. A more
usable model would be to treat each word deletion as a single action and undo
them one by one. (I think this is what just about every other text editor that
I've used does.) Probably only consecutive single character inserts and deletes
should be coalesced on the undo stack.

Reproducible: Always

Steps to Reproduce:
1. type "foo bla bar foobar"
2. press Ctrl-Backspace three times, so that it's right after "foo "
3. undo


Actual Results:  
Editor shows "foo bla bar foobar"

Expected Results:  
It should have showed "foo bla"

Comment 1

[Kathleen :Brade]

I don't agree with this bug.  However, I could be convinced.  What is the
behavior of other applications?

Comment 2

[Davor Cubranic]

Of the editors I have installed on my machine, Eclipse and Word behave as
expected: consecutive single-character deletes are undone as a unit, but
consecutive word deletions are undone one at a time.

Emacs does not coalesce anything for undo. As far as I can tell, even
single-character deletions have to be undone one by one.

Comment 3

[Gervase Markham [:gerv]]

This is an automated message, with ID "auto-resolve01".

This bug has had no comments for a long time. Statistically, we have found that
bug reports that have not been confirmed by a second user after three months are
highly unlikely to be the source of a fix to the code.

While your input is very important to us, our resources are limited and so we
are asking for your help in focussing our efforts. If you can still reproduce
this problem in the latest version of the product (see below for how to obtain a
copy) or, for feature requests, if it's not present in the latest version and
you still believe we should implement it, please visit the URL of this bug
(given at the top of this mail) and add a comment to that effect, giving more
reproduction information if you have it.

If it is not a problem any longer, you need take no action. If this bug is not
changed in any way in the next two weeks, it will be automatically resolved.
Thank you for your help in this matter.

The latest beta releases can be obtained from:
Firefox:     http://www.mozilla.org/projects/firefox/
Thunderbird: http://www.mozilla.org/products/thunderbird/releases/1.5beta1.html
Seamonkey:   http://www.mozilla.org/projects/seamonkey/

Comment 4

[Davor Cubranic]

Any thoughts on changing this behaviour? If the intention is to have editing in
Mozilla applications behave as closely as possible to other common applications,
I really think we should not coalesce consecutive Ctrl-Backspaces for the
purpose of Undo.

Comment 5

[Rainer Bielefeld]

Still Reproducible with German SeaMonkey 2.32.1 Build 20150204202218 on German WIN7 64bit:

Please compare:
Libreoffice:
0. Open empty new writer document
1. type "This is a nice little sentence"
2. <control+z> ony by one 
   » Sentence will be deleted word by word (more or less)
     this is the way how I see that in lots of other applications.

Now try Seamonkey:
10. Launch Seamonkey ► open MailNews ► [Compose]
11. type "This is a nice little sentence"
12. <control+z> ony by one 
   » Sentence will be deleted completely
     I can't find any good reason for such a behavior.

May be we will need a more detailed specification how Undo should work in different cases?
Is there any knowledge how that worked in the very early times of Mozilla?

Mail editing, Seamonkey coposer and also Browser for Text editing areas (like Comment area here in bugzilla) are affected.

I did not find a clear DUP of this one

Summary should be modified to a more meaningful: Undo for text edits coalesces too many edit actions.

I wonder whether this one might be related to "Bug 1070707 - "Undo" function messes up text sometimes" - I stumbled upon this one during my tests there. May be someone wants to add a "see also"? I do not have permissions.

Comment 6

[Rainer Bielefeld]

At <de.comm.software.mozilla.misc> in thread "SM: Bugs bestätigen 2015-02 -- Bug 1070707 - Rueckgaengig zerstoert Texte " Peter Baetz also confirmed this problem for Linux. 
Can someone please amend OS-Picker? I do not have permissions.

Comment 7

[Rainer Bielefeld]

Affected "edit actions" only seem to be text typing or deleting. Applying formatting like Character color, bold/italic, hyperlinks and so on seem to work more or less as expected. Only text adding or text deleting is not enough subdivided.

Comment 8

[Anje]

In Write window using Vista and version 45.3.0
Observed behaviour.
Using 'Body Text' as default.

Observation 1:
Type without making any formatting or editing of text - strictly no changes. You could type several sentences and even use return twice and start another paragraph.
If you now use 'Edit' >'Undo' or 'Ctrl +Z'
Result: the entire text...everything will be removed.

Observation 2:
Start typing as before making no changes at all in formatting or backspacing etc.
Then swap to 'Paragraph' mode
Repeat typing, no formatting or backspacing, just type as is.
If you now use 'Edit' >'Undo' or 'Ctrl +Z'
Result: Everything you typed after entering 'paragraph' mode will be removed.
If you now use 'Edit' >'Undo' or 'Ctrl +Z'
the paragraph inserted blank line is removed.
If you now use 'Edit' >'Undo' or 'Ctrl +Z'
The entire first paragraph in Body Text is removed.

Observation3:
Type again, but this time stop and highlight a word, type some more and choose some other formatting like italic, then type and use backspace to correct a word. Finally finish the sentence.
If you now use 'Edit' >'Undo' or 'Ctrl +Z'
You will now find that any text which occured after any formatting or correctional backspace etc will be removed up to point of previous change of formatting.
repeated use of 'Undo' follows the same pattern.

So the Undo action will remove everything that has the same format applied or back to any use of eg: backspace to correct a word. Use of the 'Return/Enter' key does not effect anything.

So 'Undo' seems to mean undo everything back to the last formatting change or editing of a mispelt word, such as backspace.
So, if user types the wrong word and chooses to use 'Undo' thinking it will undo that word, eg: undo back to a previous space, they discover the whole email content is removed. 

I'm not proposing what the expected behaviour should be, but it could be confusing if it is not understood what 'Undo' does in a Write message.

Comment 9

[Jens Stutte [:jstutte]]

Bulk-downgrade of unassigned, 4 years untouched DOM/Storage bugs' priority.

If you have reason to believe this is wrong (especially for the severity), please write a comment and ni :jstutte.