Mailing List Archive

VNC keyboard/mouse problem
I am running RealVNC vncserver 4.1.2 on FC8, vncviewer on XP. Things are
running well and then suddenly left click on the mouse moves windows instead
of doing the usual left mouse operations. I think it is behaving as if the
ALT key is locked down. (Nothing else on the XP side has this problem, so it
is not like the ALT key is actually locked by Sticky Keys.)

The symptoms seem to be associated with Eclipse 3.4. That is the main program
I am running, so it is possible other programs could cause the problem. In
Eclipse, the problem seems to be related to selecting a region using
programmatic control, rather than the mouse. For instance, SHIFT-ALT-Up
extends the region to the next larger java expression. The problem tends to
occur when the region is more than one line. (Similar behavior in emacs does
not seem to reproduce the problem.)

I can reproduce the bug by running the viewer at 256 colors, and using
SHIFT-ALT-Up in java code within the Eclipse editor. Eventually, the region
gets big enough and the keys start to behave as described.

Disconnecting and reconnecting the viewer does not reset the mouse/keyboard
behavior, so it isn't the viewer that is at fault.

The lower the color level is, the larger the area that can be selected before
the problem manifests itself.

(0) Has anyone else reported a similar problem?

(1) Is there anything I can run that will echo what the Xserver thinks it is
receiving? And is there something similar to capture mouse events?

(2) Is there any setting of the server that would result in this behavior? If
so, I could try to reset it. Currently, I need to exit everything and kill
the vnc session.


If I can isolate the problem to something Eclipse is doing wrong in its
interactions with Xvnc, I'll submit the bug to Eclipse. I cannot run in an X
client now because of bandwidth limits, but when I get a chance, I'll see if I
can reproduce the problem without VNC.


Thanks.



Gary Levin
RRC 1N345
Telcordia Technologies
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RE: VNC keyboard/mouse problem [ In reply to ]
I have tried to reproduce the problem with Eclipse running with the cygwin X
server as my display and the problem does not manifest itself. This suggests
that while Eclipse is tripping the problem, there is some fault in Xvnc.

Is there some logging that can be turned on in Xvnc that would provide useful
information about what Eclipse is sending to the server that is resulting in
the problem?

Gary Levin
RRC 1N345
Telcordia Technologies


> -----Original Message-----
> From: vnc-list-admin@realvnc.com
> [mailto:vnc-list-admin@realvnc.com] On Behalf Of Levin, Gary Marc
> Sent: Saturday, December 20, 2008 11:42 PM
> To: vnc-list@realvnc.com
> Subject: VNC keyboard/mouse problem
>
> I am running RealVNC vncserver 4.1.2 on FC8, vncviewer on XP.
> Things are
> running well and then suddenly left click on the mouse moves
> windows instead
> of doing the usual left mouse operations. I think it is
> behaving as if the
> ALT key is locked down. (Nothing else on the XP side has
> this problem, so it
> is not like the ALT key is actually locked by Sticky Keys.)
>
> The symptoms seem to be associated with Eclipse 3.4. That is
> the main program
> I am running, so it is possible other programs could cause
> the problem. In
> Eclipse, the problem seems to be related to selecting a region using
> programmatic control, rather than the mouse. For instance,
> SHIFT-ALT-Up
> extends the region to the next larger java expression. The
> problem tends to
> occur when the region is more than one line. (Similar
> behavior in emacs does
> not seem to reproduce the problem.)
>
> I can reproduce the bug by running the viewer at 256 colors, and using
> SHIFT-ALT-Up in java code within the Eclipse editor.
> Eventually, the region
> gets big enough and the keys start to behave as described.
>
> Disconnecting and reconnecting the viewer does not reset the
> mouse/keyboard
> behavior, so it isn't the viewer that is at fault.
>
> The lower the color level is, the larger the area that can be
> selected before
> the problem manifests itself.
>
> (0) Has anyone else reported a similar problem?
>
> (1) Is there anything I can run that will echo what the
> Xserver thinks it is
> receiving? And is there something similar to capture mouse events?
>
> (2) Is there any setting of the server that would result in
> this behavior? If
> so, I could try to reset it. Currently, I need to exit
> everything and kill
> the vnc session.
>
>
> If I can isolate the problem to something Eclipse is doing
> wrong in its
> interactions with Xvnc, I'll submit the bug to Eclipse. I
> cannot run in an X
> client now because of bandwidth limits, but when I get a
> chance, I'll see if I
> can reproduce the problem without VNC.
>
>
> Thanks.
>
>
>
> Gary Levin
> RRC 1N345
> Telcordia Technologies
> _______________________________________________
> VNC-List mailing list
> VNC-List@realvnc.com
> To remove yourself from the list visit:
> http://www.realvnc.com/mailman/listinfo/vnc-list
>
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Re: VNC keyboard/mouse problem [ In reply to ]
On Dec 23, 2008, at 8:26 AM, Levin, Gary Marc wrote:

> I have tried to reproduce the problem with Eclipse running with the
> cygwin X
> server as my display and the problem does not manifest itself. This
> suggests
> that while Eclipse is tripping the problem, there is some fault in
> Xvnc.
>
> Is there some logging that can be turned on in Xvnc that would
> provide useful
> information about what Eclipse is sending to the server that is
> resulting in
> the problem?
>
> Gary Levin
> RRC 1N345
> Telcordia Technologies

It's not eclipse. It has to do with losing focus on the VNC window
while a modifier key is pressed. I.e., hold down 'control' inside the
VNC window, switch out of that with (with CTRL-Tab, for example) and
then go back into the session and your CTRL key might be "locked" on.
You have to tap control or shift or alt to unstick it.

I have no idea what is a reasonable solution to this problem, as
everything I can think of might not be what you want.

Sean
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Re: VNC keyboard/mouse problem [ In reply to ]
This is likely neither relevant nor helpful, but I've had a similar
problem from a RealVNC viewer on Mac OS X to a server on a Windows
machine running XP.

If I use the Mac 'Command' key within VNCViewer, the (equivalent ?)
'Control' key on the Windows box sometimes gets locked... and I have to
end the VNC session and start a new one to correct it.

I've found if I simply click 'out' of the VNCViewer window (so it's no
longer frontmost before using the problematic modifier key), the remote
key locking symptom does *not* occur.

FWIW

Peter B.

-----
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RE: VNC keyboard/mouse problem [ In reply to ]
Thanks for the suggestion, but I cannot seem to switch out of the VNC window
while holding down the CTRL key. (I am running under XP, if that matters.)
Also, I have tried tapping the control, shift, alt keys, and none of them
solves the problem. The vnc menu does not show alt or ctrl checked and
checking them and unchecking them has no effect either.

Regarding work-arounds, turning off ALT would not be helpful; I need to be
able to send the modifier keys (for editting in eclipse). On the other hand,
something simple like tapping the modifiers if it locks up, or even running an
app to reset the Xvnc server to a sane setting would be an acceptable
work-around.

Gary Levin
RRC 1N345
Telcordia Technologies


> -----Original Message-----
> From: Sean Kamath [mailto:kamath@geekoids.com]
> Sent: Tuesday, December 23, 2008 2:47 PM
> To: Levin, Gary Marc
> Cc: vnc-list@realvnc.com
> Subject: Re: VNC keyboard/mouse problem
>
>
> On Dec 23, 2008, at 8:26 AM, Levin, Gary Marc wrote:
>
> > I have tried to reproduce the problem with Eclipse running with the
> > cygwin X
> > server as my display and the problem does not manifest itself. This
> > suggests
> > that while Eclipse is tripping the problem, there is some fault in
> > Xvnc.
> >
> > Is there some logging that can be turned on in Xvnc that would
> > provide useful
> > information about what Eclipse is sending to the server that is
> > resulting in
> > the problem?
> >
> > Gary Levin
> > RRC 1N345
> > Telcordia Technologies
>
> It's not eclipse. It has to do with losing focus on the VNC window
> while a modifier key is pressed. I.e., hold down 'control' inside the
> VNC window, switch out of that with (with CTRL-Tab, for example) and
> then go back into the session and your CTRL key might be "locked" on.
> You have to tap control or shift or alt to unstick it.
>
> I have no idea what is a reasonable solution to this problem, as
> everything I can think of might not be what you want.
>
> Sean
>
>
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