Here are some of the obscure messages when you try and run some programs from an xterm using Xvnc4 as a display...
mtf@poseidon:~$ glxgears Error: couldn't get an RGB, Double-buffered visual
mtf@poseidon:~$ quadrapassel Failed to initialise clutter: Unable to find suitable fbconfig for the GLX context
mtf@poseidon:~$ glxinfo name of display: ::ffff:127.0.0.1:4.0 Error: couldn't find RGB GLX visual or fbconfig
Here are some of the obscure messages when you try and run some programs from an xterm using Xvnc4 as a display...
mtf@poseidon:~$ glxgears
Error: couldn't get an RGB, Double-buffered visual
mtf@poseidon:~$ quadrapassel
Failed to initialise clutter: Unable to find suitable fbconfig for the GLX context
mtf@poseidon:~$ glxinfo 127.0.0. 1:4.0
name of display: ::ffff:
Error: couldn't find RGB GLX visual or fbconfig