With Progressive Display enabled, some web page images flickers when viewed on Windows 7 and Windows XP client devices as the mouse pointer moves back and forth over the images. The issue is the result of a conflict between Windows Internet Explorer 8 and the Progressive Display feature when using Off Screen Surfaces (OSS).

Caution! Refer to the Disclaimer at the end of this article before using Registry Editor.

To resolve this issue, disable the use of OSS on the Virtual Desktop Agent (VDA) or on the Receiver.

To disable OSS on the Receiver, set the EnableOSS registry value as follows:

HKEY_CURRENT_USER\Software\Citrix\ICA Client\Engine\Lockdown Profiles\All Regions\Lockdown\Virtual Channels\Thinwire Graphics\

Name: EnableOss

Type: REG_SZ

Data: False

To disable OSS on VDAs versioned XDE400VDAWX86006 or 5.0, set the following registry value as follows:

HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\Graphics\

Name: DisableOss

Type: REG_DWORD

Data: 1

Important! The DisableOSS registry value does not apply to VDA versions 5.5 and later. In order to allow use of OSS where necessary, these versions use the per process method outlined in CTX132709 - Colors in Graphics-Specific or Intensive Applications are Not Displayed Correctly.

To disable OSS on XenApp 6.0, set the following registry value as follows:

HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\Graphics\

Name: DisableOss

Type: REG_DWORD

Data: 1

Problem Cause

This issue is the result of a conflict between the application in question and the Progressive Display or Adaptive Display feature when using OSS.