Spurious pastes

[Jon Turney]

On 02/02/2018 22:26, David Mathog wrote:
> In the last few days nedit on those remote machines has been doing 
> spurious pastes. That is, whatever is currently in the X11 paste 
> buffer (not the program's paste buffer) is ending up dropped into 
> whatever file is being edited. Unclear why they are landing where 
> they do, I have not actually seen it happen, just found it when diff 
> indicated these odd insertions. My best guess is that these happen 
> while I am scrolling over these regions. Needless to say, this is 
> really not a good thing.
> 
> There have been only two changes recently.
> 
> 1. I cleaned my mouse. 2. yum on 1/27/18 automatically installed on 
> those servers: xorg-x11-server-common-1.17.4-16.el6.centos.1.x86_64
> 
> To eliminate (1) the mouse was swapped with another one. Too soon to
>  know if that did anything.

I wonder if you aren't somehow accidentally clicking the middle mouse 
button whilst scrolling?

> On 02-Feb-2018 13:13, David Mathog wrote:
>> I seem to recall that before this if I highlighted a region in an
>> xterm window, then moved to another X11 application window, and center
>> clicked, it would paste the highlighted text.  However, if nothing was
>> highlighted in the last window, nothing would paste.  My memory may be
>> faulty on this issue though, as I never paid a lot of attention to it
>> before it started misbehaving.
> 
> That wasn't right, but cut/paste is slightly different between "on the 
> console" and "over putty ssh tunnel with X11 Server on Windows".
> 
> On an XFCE4 ubuntu system console this is what happens:

I'm guessing this means a non-X terminal?

> 1.  type "pwd<enter>" into an uxterm window
> 2.  highlight "pwd" on the line at the preceding prompt, center
>      click once at the current prompt.  "pwd" is pasted.
>  Â Â Â  Press "enter".
> 3.  left click once on the still highlighted "pwd", now 2 lines up.
>      The highlight goes away.  Center click once at the prompt.
>  Â Â Â  "pwd" is still pasted. Press "enter".
> 4.  With the left mouse button drag across any letter and back
>      to the original position.  So nothing is highlighted.  This can
>      be on any text anywhere in the window.  Center click
>      at the prompt.  Nothing is pasted - the paste buffer is now
>  Â Â Â  empty.
> 
> So on the console it is possible to select "nothing".
> 
> On the X11 server ssh to the Ubuntu system and it is the same for the 
> first 3 steps, but the 4th still pastes "pwd".  The rule seems to be 
> "paste buffer can be replaced by anything selected, but not by a select 
> operation which ends with nothing highlighted."
> 
> On the X11 server ssh to the Centos system, it behaves just like a 
> similar connection to the Centos system.
> 
> The operations do the same thing when going between two uxterm windows 
> on any of these tests.
> 
> Which is right?  Is "nothing" a valid thing to load into the paste 
> buffer or no?

 From the testing I did on a couple of linux systems, making an empty 
selection in urxvt doesn't change the clipboard contents, so I don't 
think this is specifically a Cygwin X server problem.

I think it's up to the client (i.e. urxvt) how it interprets making an 
empty selection, which seems to be to not update the selection.

> Is there a standard way to clear this buffer?

I was going to suggest 'xsel -c' or 'xclip -i /dev/null', but that 
doesn't work (in this case) for obscure reasons to do with cut buffers...


For future issues, can I ask you to use the cygwin list, per [1]

[1] https://cygwin.com/ml/cygwin-xfree-announce/2015-03/msg00001.html


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