When publishing an application on XenApp 5.0, XenApp 6, or XenApp 6.5 on Windows 2008/R2 Server, the application appears with the Windows classic title bar as shown in the following screen shot.

To implement an Aero theme (Windows Vista) on Windows 2008/2008 R2server for published applications, complete the following instructions:
The Desktop Experience feature is enabled by default in XenApp 6.5 installations (please proceed to Widows Server 2008 R2 XenApp 6 / XenApp 6.5 Group Policy)

1. Click Start and select Server Manager.

2. Go to the left pane and select Features > Add Features.

3. Select the Desktop Experience checkbox.

4. Click Next and then Install.

5. After the installation is complete, restart the server.

6. Type Services.msc at the run line and press Enter.

7. Ensure that the Services Theme is started and set to start automatically. 

8. Right-click the desktop and select Personalize > Theme > Windows Vista.

9. Click OK.

10. The following group policies must be applied to all users:
    Windows Server 2008 XenApp 5 Group Policy
    Policy: User Configuration - Administration Templates - Control Panel - Display - Desktop Themes - Load a specific visual style file of force windows Classic – Enabled
    Point the group policy to installed C:\Windows\Resources\Themes\Aero\aero.msstyles
    
    Widows Server 2008 R2 XenApp 6 / XenApp 6.5 Group Policy
    Policy: User Configuration - Administration Templates - Control Panel - Personalization – Force a specific visual style file or force windows Classic – Enabled
    Point the group policy to installed C:\Windows\Resources\Themes\Aero\aero.msstyles

The title bar of published applications must now be Aero style theme:

Problem Cause

This is by design, in Windows Server 2008/Windows Server 2008 R2 the server native theme is the Windows Classic. By default, all applications published on the server apply the Windows Classic Theme.