Disclaimer: this information was submitted by an affected user and is provided "AS IS" with no warranties. The following steps were not verified or tested by us.

Apply the GPO setting “Best Performance” option to the XenApp servers (this is done per user and cannot be set at the build level):

Change the visual effects on a per user basis to Adjust for best performance. This was applied to the Citrix Application server by GPO 

User Configuration
Preferences
Windows Settings
Registry
VisualFXSetting (Order: 1)General
Action

Update

Properties
Hive

HKEY_CURRENT_USER

Key path

SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\VisualEffects

Value name

VisualFXSetting

Value type

REG_DWORD

Value data
and:
User Configuration
Administrative Templates
Control Panel/Personalization
Policy Setting Comment
Load a specific theme Enabled
Path to theme file: %Systemroot%\Resources\Ease of Access Themes\basic.theme

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