With the full support for Aero redirection that came with Citrix XenDesktop 5.5, there has been some problems with it being disabled.
I've heard this from several people, but my demo environment works great!
When slow client endpoint is detected, Aero redirection is turned off for the session and the Windows basic theme is enabled. It is possible to prevent Aero redirection from being disabled by modifying a registry key on the Virtual Desktop Agent (VDA).
Please note that it only applies to XenDesktop 5.5 on Windows 7. Not, Windows Vista and not Windows XP!
According to the design, when an Aero redirection enabled client endpoint is unable to sustain rendering graphics at least at a rate of 5 FPS (frames per second), for a period of 10 seconds, Aero theme is disabled for the session.
The key MinFps can be modified in the registry of the VDA to prevent disabling of Aero redirection. To modify the value, edit the system registry.
Caution! This fix requires you to edit the registry. Using Registry Editor incorrectly can cause serious problems that might require you to reinstall your operating system. Citrix cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk. Be sure to back up the registry before you edit it.
Disconnect and reconnect the desktop session for this change to take effect.
By default, the value of MinFps is 5, which means, Aero redirection is disabled when graphics rendering is not sustained at 5 FPS, while the feature is enabled.