[CentOS] CentOS7: vncserver - desktop resolution

Hi,

I just installed CentOS7 and managed to start the vncserver service, but 
once I connect to the machine, the desktop resolution isn't the one 
which I set in the vncserver@:3.service file located in 
/lib/systemd/system/ directory.

The content of the mention file:
----------------------------------------
[Unit]
Description=Remote desktop service (VNC)
After=syslog.target network.target

[Service]
Type=forking
# Clean any existing files in /tmp/.X11-unix environment
ExecStartPre=/bin/sh -c '/usr/bin/vncserver -kill %i > /dev/null 2>&1 || :'
ExecStart=/sbin/runuser -l foo -c "/usr/bin/vncserver %i -geometry 
1400x800 -nolisten tcp -localhost"
PIDFile=/home/foo/.vnc/%H%i.pid
ExecStop=/bin/sh -c '/usr/bin/vncserver -kill %i > /dev/null 2>&1 || :'

[Install]
WantedBy=multi-user.target
------------------------------------------

The desktop resolution is different (more than my NB display can 
display) and the scroll bars appear.

The same behaviour occurs when I start the vncserver from commant line:
  vncserver :4 -geometry 1400x800 -nolisten tcp -localhost
and then connect via ssh
  vncconfig -display :4 -connect localhost:49999

In CentOS6 I had no problem with this. The desktop resolution adjusted 
according the -geometry parameter.

Please, let me know, if you have any idea.

thanks

martin