The protocols don't diverge, they just have different encodings. Encodings have nothing to 
do with the input messages.  
 
Which extra-characters do you see, the one you typed or others? And can you see the 
same effect with other clients? 
 
 

Yes, I see the same character duplicated.  So if I hit the 'a', I get 'aaa'. 
 
I see this also with tightvnc viewer 1.2.6 for linux as well.  All has worked fine 
before about 10 days ago or so.  Also, it makes no difference if it's a KDE 
application or a GTK+ application, just in case you were wondering about 
differences in their event handling perhaps ? 

So what did you do/change 10 days ago? Maybe updated the X11 server? 
Does it also happen with krdc? 
 
 
 
 
 

Nothing I don't think.  I just did a normal update of kdelibs, kdebase, kdenetwork, 
and kdepim I believe (cvs up I mean)...  I have not updated X for months and 
nothing in my config has changed really. 
 
Currently the only kde box I have access to is my own so I can't run kdrc and 
connect to myself. I'm in the process of upgrading to xfree 4.3 now and I'll be 
updating my qt along with it, I'll still be running qt3.1 though.  I'll see if that clears 
this up. 
 
Hmm, I did upgrade my kernel about 3 weeks ago though... Maybe I actually seen 
the problem then as well. The only thing that changed in my config was the 
addition of low latency and preemptabilty; likely candidates for problems esp. in 
the 2.4 series of kernels ... If after my upgrade things are still messed up, I'll try 
disabling those options in my kernel. 

Doesn't seem like preempt had anything to do with it. I'm now running a 
non-preemptable kernel, QT 3.1.2, XFree 4.3, and a very recent snapshot of 
kdenetwork. 
 
I have noticed that krfb now requires a helper thread or process, I don't always 
remember this being the case because my load used to always be 1.0 when 
running vnc but now it's 2.0 because there are 2 krfb processes working.  I take 
it that this is to be expected.  I only bring this up because the duplicated keys are 
worse when the system load is high. If it's just 2.0 then I get a 'normal' duplication 
of 3 or 4 additional characters.  If my load is any higher then I get a few dozen 
duplicated characters ... this isn't any fun when that character is <Ctrl-V> ...  
 
Do I have an old setup somehow that hasn't been overwritten since I've been 
running kde-cvs straight for about 7 months now without a complete wipe of my 
~/.kde/share or $KDEDIR/share ?? Although I have tried wiping out my 
$KDEDIR/share directory several times. 

krfb 0.5 used a different backend than 0.6. Later versions use threads.   The old setup shouldnt be relevant. But the relationship with the system load is interesting. Do you, maybe, have a very high key-repeat rate or a very slow CPU? In that case the problem may make sense, because VNC uses key up and key down commands. If the time between these commands is too long, for whatever reason, the keys wll be repeated. 

PIII 500MHz 
KControl: 
Keyboard Repeat Delay: 250ms 
Keyboard Repeat Rate: 30/s 
 
QTConfig 
Cursor Flash Time: 500ms 
 
Anything not seem right?  Krfb used to work really well but I still say it's my setup 
somehow and I'm considering closing the bug.  2.4.20 seems to not like 
interactive workloads at all ... On another note, might there be a way to lessen 
the load of the whole process? A load of 2 doesn't seem right when I'm sitting 
idle and nothing is being transmitted over the network. 
 
 

I am not sure how accurate the load factor is. krfb is permanently polling the X11 server 
for changes, thus the two processes are playing ping pong. The third process is the 
thread that runs the network connection. So it may be correct. Whether it sends data 
over the network or not only affects the network thread, krfb keeps polling for changes. 
This can only be changed by improving X11. The performance hit is hardly noticable on 
my machines, unless I watch a video, play a game or something similar.  
 

I can't reproduce this bug, and there is nothing that I could do to prevent this. The VNC 
protocol transmits messages when a key goes up or down, and I just forward this to the 
X11 server. 

I see this frequently as well when using either TightVNC V1.2.9 on Linux or krdc, connecting to krfb as part of Suse 9.0/KDE 3.2.0.  I'm running X 4.4, the clients are running 4.3 as shipped and upgraded with SuSE.

If I have KDE listen for desktop sharing requests, this happens to me as well.  This didn't happen until I updated into the later KDE 3.1.X series as well as the KDE 3.2.X series.  If I type into a term windo that I can see from accessing my KDE workstation remotely, I will get multiple characters of varying amount that will appear.  It happens on lower bandwidth connections.  Generally its as if it is waiting to receive more data from the connection, and the last thing it sae me do was press a key, it leaves it in the state that I am holding the key down rather than see it as a key depress.  So characters are scattered.  This is still a bug.

I have the same problem (single keystrokes appearing multiple times) with Suse 9.1 and KDE 3.2.2. I did not have the problem earlier (3.1.x), but it appeared a while ago (I think Suse 8.2 or 9.0 and some later 3.1.x or earlier 3.2.x version).

This makes working over a VNC connection almost impossible. I'm using tightvnc as a client (running under Windows and Linux).

This really is still a bug.

This bug appears after I upgraded my box from RedHat 8.0 to Fedora Core 2. The excessive characters makes desktop sharing not usable. Can anyone suggest other ways for sharing root display? I heard VNC 4.0 adds this feature, but does it work with x.org (rather than XFree86)? 

I don't know why this bug was closed.
It's a duplicate of http://bugs.kde.org/show_bug.cgi?id=84204

A quick solution is to type "xset r off" when you log in to your VNC session.