GNOME 3 requires all of the following extensions: Composite, Damage, GLX (configured for Direct rendering mode), RANDR, Render, Shape, Sync, X Big Request, X Fixes, XFree86 Big Font, X Generic Event, X Input, X Keyboard, and X Test. Without these extensions enabled, the GNOME 3 Desktop and the GDM Login Screen (when using XDMCP) display either a blank window or a GNOME error message.
You can ensure your session definition meets the requirements for a desktop or client launched from a modern Linux operating system by using one of the following sample session definitions or by creating a new session definition:
You can use either the My desktop (GNOME 3) or X terminal desktop (GNOME 3) sample session definitions to connect to a modern operating system. (These session definitions are preconfigured for a GNOME 3 environment). If they are not listed in the X Manager window under Session Definitions, you can add them by importing the linux_gnome3_templates.rxd template file. (See Import Installed Templates.)
You can create a new session definition by clicking the Plus button next to Session Definitions in the X Manager window. (See Session Definition.)
Optimizing X Client Network Performance
The GNOME 3 Desktop and modern X clients require a lot of bandwidth. You can improve performance on a high latency network or VPN by using a distributed session. With this configuration, the X11 traffic does not have to travel through the high latency network. Only the required protocol and data is transmitted. You can use a distributed session in either Standalone mode or in Domain mode:
If you're using X Manager, see How to Configure a Distributed Session in Standalone Mode.
If you're using X Manager for Domains, see Domain Setup: Improve Performance Over a Slow Network.