After connecting host clipboard isnt working anymore

[mavarazo]

Hello,

After connecting to the client (CentOS) the clipboard entirely stops working on the host (Win10).
When I close the viewer, everything goes back to normal.

Anyone else detected this behavior? Does anybody know a workaround?

Thanks alot.

[CendioOssman]

I'm afraid I'm slightly confused by your wording here.

Are you running WinVNC on the Windows 10 machine, and vncviewer on CentOS?

Are both 1.8.0?

[mavarazo]

Sorry... didnt want to confuse...

Im using vncviewer on Win10 to connect to CentOS

[CendioOssman]

How are you starting the server on CentOS? And which versions are you using?

[mavarazo]

Using: tigervnc-server-1.8.0-1.e17.x86_64
Start: vncserver
Xstartup:

unset SESSION_MANAGER
unset DBUS_SESSION_BUS_ADDRESS
exec /etc/X11/xinit/xinitrc
vncconfig -nowin &

[CendioOssman]

And you are using tigervnc 1.8.0 on the client as well?

Does it help to disable the clipboard in the viewer settings?

[Pascal666]

Same problem. vncviewer64-1.6.0 on Windows 7. Windows unable to add data to clipboard after Yum upgraded CentOS to 7.4 which included tigervnc-server-1.8.0-1.el7.x86_64.

To downgrade to the version of TigerVNC shipped with CentOS 7.3:
yum downgrade http://vault.centos.org/7.3.1611/os/x86_64/Packages/tigervnc-license-1.3.1-9.el7.noarch.rpm http://vault.centos.org/7.3.1611/os/x86_64/Packages/tigervnc-server-1.3.1-9.el7.x86_64.rpm http://vault.centos.org/7.3.1611/os/x86_64/Packages/tigervnc-server-minimal-1.3.1-9.el7.x86_64.rpm
add exclude=tigervnc* to [base] section of /etc/yum.repos.d/CentOS-Base.repo to prevent the broken version from being automatically reinstalled.

[mavarazo]

@CendioOssman : Yes, i tried vncviewer64_1.7.1 and vncviewer64_1.8.0

@Pascal666 : Thanks for your workaround. After downgrade, tigervnc works like a charm.

[CendioOssman]

I'm afraid I'm unable to reproduce this issue with the RHEL 7 machine I have here. I tried both Windows 7 and Windows 10 as clients.

Are you running the standard Gnome classic desktop?

Do you have any other software installed on your clients that might mess with the clipboard? E.g. Microsoft Office has been known to do so in the past.

[mavarazo]

On CentOS I'm forced to use KDE.
On Windows 10 I've installed Microsoft Office because its the office workstation.

[CendioOssman]

I switched to KDE here and still no issues.

Could you try turning off any Office stuff running locally just to see if that is indeed the issue? You may need to hunt for background stuff as well.

[Pascal666]

I too am running KDE. I have Office 2003 installed but was able to reproduce the problem even without it running. The problem does not occur until you add something to the clipboard on Linux.

I use PuTTY on Windows. Normally I can highlight text and then click elsewhere in the window to copy it. Normally if I highlight text in a PuTTY window, then switch to a different window and add something to the clipboard, the highlight will go away. When this problem is occurring, as soon as I release the mouse from highlighting text the highlight goes away. It acts like Linux is constantly overwriting the Windows clipboard.

I was able to reproduce this on a new CentOS 7.4 install:
Complete a minimal install
Create a user
yum install tigervnc-server kde-workspace
change the username twice in /usr/lib/systemd/system/vncserver@.service
systemctl enable vncserver@:0
create /home/user/.vnc/passwd
mkdir -p /home/user/.local/share
chown user:user -R /home/user/.local
reboot

[bphinz]

Check to see if klipper is running in the background. It's notorious for interfering with VNC clipboard transfers.

[Pascal666]

@bphinz Yes, KDE on CentOS 7 includes Klipper. It did not change from 7.3 to 7.4. Exiting Klipper does appear to be another workaround.

I tested tigervnc-server 1.7.1 from https://dl.bintray.com/tigervnc/stable/el7/RPMS/x86_64/ and it does not have this problem. 1.8.0 from there does. The release notes for 1.8.0 state "vncconfig no longer needed for clipboard with Xvnc/libvnc.so". Perhaps something in that change is causing this problem?

[CendioOssman]

@bphinz Yes, KDE on CentOS 7 includes Klipper. It did not change from 7.3 to 7.4. Exiting Klipper does appear to be another workaround.

I'm afraid there's not much we can do then. TigerVNC and Klipper both try to do the same thing, which ends up in the scenario you're seeing. So you need to reconfigure something:

a) Disable clipboard in TigerVNC
b) Disable Klipper
c) Disable PRIMARY sync in TigerVNC
d) Disable PRIMARY sync in Klipper

I tested tigervnc-server 1.7.1 from https://dl.bintray.com/tigervnc/stable/el7/RPMS/x86_64/ and it does not have this problem. 1.8.0 from there does. The release notes for 1.8.0 state "vncconfig no longer needed for clipboard with Xvnc/libvnc.so". Perhaps something in that change is causing this problem?

I would wager that you didn't have working clipboard in the previous version for some reason. So essentially you were using option a).