Unvisible application content within VNC / XFCE

I do have a weird render issue of some applications that I'm running within a **tigervnc** session on a remote host where **XFCE** is started. As you can see from the screenshot, while applications display correctly their content (e.g. file browser, visual studio code, ..), the matlab window does not show its content. I believe this is **not a matlab related issue** since If I run matlab through a "ssh -X" session on the same host, it is displayed properly. It might be related, I have also seen that kind of rendering issue with matplotlib when triggering the pyplot.show(), the image is kind of transparent and we see the image to display mixed with the desktop background image. If necessary, the xstartup script is

#!/bin/sh
# Start Xfce4 Desktop
[ -x /etc/vnc/xstartup ] && exec /etc/vnc/xstartup
[ -r $HOME/.Xresources ] && xrdb $HOME/.Xresources
vncconfig -iconic &
dbus-launch --exit-with-session xfce4-session &

and the vncserver is ran with vncserver -SecurityTypes None -depth 32 -geometry 1680x1050 -cleanstale Thank you very much for your help