Re: Text selection can't be erased by pressing delete

[Gabriel TEIXEIRA <gabriel_teixeira@sdesigns.eu>]

On 20/08/2010 18:42, Bob Proulx wrote:
> Gabriel TEIXEIRA wrote:
>    
>> I've been working with three simultaneous emacs windows, each one
>> containing a diferent project, and I noticed that two of those three are
>> presenting a weird behaviour.
>>      
> On what system are you running emacs?  Is this GNU/Unix, Cygwin, MSYS,
> other?  Running in a terminal window, or under a X11, or other native
> graphics?
>
>    
It is under Ubuntu Linux 10.04 x64 in the graphics mode.
>> When I select a text in those windows (like by pushing Shift and
>> then the arrow keys), and then I push the key Delete, I expect that
>> the selected/highlighted text be erased, but instead, it erases a
>> single character to the left of the cursor (like would happen
>> without the selection) and the selection disappears (although the
>> same operation works with Backspace or Shift+Delete normally).  It
>> seems that the Delete key is not anymore aware of the text
>> selection.
>>      
> That would be the "normal" traditional behavior of Emacs on Unix
> machines for all of time prior to the recent introduction of Microsoft
> key bindings.
>
>    
Which I think is a good behaviour since the delete key is just above the 
arrow keys in my keyboard while the backspace is a little further. Since 
I do selections using Shift + arrows, the delete lies just within the 
range of my middle finger, while the backspace would need to elevate the 
entire hand up to there, so I prefer use the delete. Besides the fact 
that I can just select the text and overwrite it directly.
>> It is even more weird the fact that this doesn't happen with the
>> window that I opened the last and the other windows that I opened
>> after to check the behaviour. I seems that emacs "wears" after some
>> time opened.
>>      
> That does seem strange that it would change behavior depending upon
> whether you have launched subsequent emacs processes.
>
>    
As I told already, maybe I mistyped something that led to this 
behaviour. Those instances are opened for weeks and the behaviour 
appeared after some days. I would like to know how to resolve this 
without doing the Microsoft solution (restarting emacs), which works, 
but lose all the layout of windows and the undo history.
>> Anyone have any idea of what's this? Is this a bug or I typed
>> accidentaly any command that triggers this behaviour?
>>      
> I do not use CUA mode but the behavior makes me wonder if something is
> causing it to be enabled and then disabled somehow.
>
>    http://www.emacswiki.org/CuaMode
>
> What is the behavior when using emacs without customizations?
>
>    emacs -q
>
>    
It behaves in the "normal" mode, no deletion with delete
> And without any initialization?
>
>    emacs -Q
>
>    
The same, 'course.
> Thinking that there must be something in the initialization that is
> behaving undesirably.
>    
More likely to be any crazy (or lazy) finger of mine, but I leave the 
hypotesys of "time wear", like a bug caused by any memory leak, 
overflowed counter or command that is disabling the mode unexpectedly 
(which I think is very unlikely).
> Bob
>
>    
Thanks for the advice about the cua-mode. I gave a read to the page and 
when I did M-x cua-mode, it got back to my favourite mode! Now I must 
figure out which command sequence is disabling the cua-mode in order 
that I don't do this anymore. I think that ad infinitum I will stop 
doing those mistakes. I noticed that emacs commands are easy to mistake 
one for another while typing, like, in an AZERTY kb, the C-x (one of the 
most used) for the C-w (after I deleted 100 lines of c code and saved 
the file unaware of that. By luck, I had a copy in the CVS).

Gabriel Teixeira