The performance of a WPF application that contains many visual elements becomes slow when a UI Automation client application is running

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Article ID: 978520 - View products that this article applies to.
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SYMPTOMS

Consider the following scenario:
  • You have a Microsoft .NET Framework 3.5 Service Pack 1 (SP1)-based Windows Presentation Foundation (WPF) application that contains many visual elements.
  • You run the application on one of the following computers:
    • A touch-enabled computer on which a Tablet PC Input Panel Accessory (TabTip.exe) process is running by default. For example, you run the application on a tablet computer.
    • A computer on which a User Interface (UI) Automation client application is running. Examples of UI Automation applications include Narrator, Magnifier, and UI Spy.
  • You interact with the WPF application. For example, you scroll within the application.
In this scenario, the performance of the WPF application becomes slow. The CPU usage increases, or the application responds slowly.

Note The problem does not occur in the .NET Framework 4.0.

CAUSE

This issue occurs because Accessibility clients must collect UI Automation information to interact with applications. This behavior causes WPF to start UI Automation events at the end of each layout. However, WPF checks every element in the application to determine whether to start an automation event. Therefore, the performance becomes slower, depending on the performance of the computer and on the number of elements in the WPF application.

RESOLUTION

Hotfix information

A supported hotfix is now available from Microsoft. However, it is intended to correct only the problem that this article describes. Apply it only to systems that are experiencing this specific problem.

To resolve this problem, use one of the following methods.

Method 1

Download this hotfix from the following MSDN Code Gallery Web site:
http://code.msdn.microsoft.com/KB978520
Note The MSDN Code Gallery displays the languages for which the hotfix is available. If you do not see your language listed, it is because the Code Gallery resource page is not available for that language.

Method 2

Download this hotfix rollup from the following Microsoft Connect Web site:
http://connect.microsoft.com/VisualStudio/Downloads/DownloadDetails.aspx?DownloadID=27829
Method 3

Contact Microsoft Customer Support Services to obtain the hotfix. For a complete list of Microsoft Customer Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:
http://support.microsoft.com/contactus/?ws=support
Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

This hotfix is scheduled to be included in the .NET Framework 4.0.

Prerequisites

You must have the .NET Framework 3.5 SP1 installed to apply this hotfix.

Restart requirement

You do not have to restart the computer after you apply the hotfix if affected files are not being used.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.
For all supported x86-based versions of Windows Server 2000, of Windows Server 2003, and of Windows XP
Collapse this tableExpand this table
File nameFile versionFile sizeDateTimePlatform
Presentationcore.dll3.0.6920.40274,218,88009-Mar-201000:23x86
Presentationframework.dll3.0.6920.40275,279,74409-Mar-201000:19x86
Presentationhost.exe4.0.31106.0295,26409-Mar-201000:19x86
Presentationhostdll.dll3.0.6920.4027130,40809-Mar-201000:23x86
Presentationhostproxy.dll4.0.31106.099,17609-Mar-201000:23x86
Windowsbase.dll3.0.6920.40271,249,28009-Mar-201000:23x86
For all supported x64-based versions of Windows Server 2000, of Windows Server 2003, and of Windows XP
Collapse this tableExpand this table
File nameFile versionFile sizeDateTimePlatform
Presentationcore.dll3.0.6920.40273,997,69608-Mar-201023:48x64
Presentationframework.dll3.0.6920.40274,636,67208-Mar-201023:45x64
Presentationhost.exe4.0.31106.0320,35208-Mar-201023:45x64
Presentationhostdll.dll3.0.6920.4027171,36808-Mar-201023:48x64
Presentationhostproxy.dll4.0.31106.0109,92808-Mar-201023:48x64
Windowsbase.dll3.0.6920.40271,110,01608-Mar-201023:48x64
For all supported x86-based versions of Windows Vista Service Pack 2 (SP2) and of Windows Server 2008 SP2
Collapse this tableExpand this table
File nameFile versionFile sizeDateTimePlatform
Presentationframework.dll3.0.6920.40275,279,74411-Mar-201011:47x86
Windowsbase.dll3.0.6920.40271,249,28011-Mar-201011:47x86
Presentationcore.dll3.0.6920.40274,218,88011-Mar-201011:47x86
Presentationfontcache.exe.configNot Applicable16103-Apr-200921:25Not Applicable
Wpfgfx_v0300.dll3.0.6920.40031,736,02417-Jun-200908:03x86
Presentationframework.dll3.0.6920.40275,279,74411-Mar-201011:47x86
Presentationhostdll.dll3.0.6920.4027130,40811-Mar-201011:47x86
Presentationhost.exe4.0.31106.0295,26411-Mar-201011:48x86
Presentationhostproxy.dll4.0.31106.099,17611-Mar-201011:48x86
Windowsbase.dll3.0.6920.40271,249,28011-Mar-201011:47x86
For all supported x64-based versions of Windows Vista SP2 and of Windows Server 2008 SP2
Collapse this tableExpand this table
File nameFile versionFile sizeDateTimePlatform
Presentationcore.dll3.0.6920.40273,997,69611-Mar-201011:46x64
Presentationfontcache.exe.configNot Applicable16103-Apr-200920:58Not Applicable
Wpfgfx_v0300.dll3.0.6920.40032,254,16817-Jun-200908:03x64
Presentationframework.dll3.0.6920.40274,636,67211-Mar-201013:48x64
Presentationhostdll.dll3.0.6920.4027171,36811-Mar-201013:48x64
Presentationhost.exe4.0.31106.0320,35211-Mar-201013:48x64
Presentationhostproxy.dll4.0.31106.0109,92811-Mar-201013:48x64
Windowsbase.dll3.0.6920.40271,110,01611-Mar-201013:48x64
Presentationframework.dll3.0.6920.40275,279,74411-Mar-201011:47x64
Windowsbase.dll3.0.6920.40271,249,28011-Mar-201011:47x64
For all supported x86-based versions of Windows 7
Collapse this tableExpand this table
File nameFile versionFile sizeDateTimePlatform
Presentationframework.dll3.0.6920.50085,279,74417-Mar-201005:15x86
Windowsbase.dll3.0.6920.50081,253,37617-Mar-201005:15x86
Presentationcore.dll3.0.6920.50084,218,88017-Mar-201005:15x86
Presentationfontcache.exe.configNot Applicable16110-Jun-200921:14Not Applicable
Wpfgfx_v0300.dll3.0.6920.49021,736,53610-Jun-200921:14x86
Presentationframework.dll3.0.6920.50085,279,74417-Mar-201005:15x86
Presentationhostdll.dll3.0.6920.5008130,40817-Mar-201005:15x86
Presentationhost.exe4.0.31106.0295,26417-Mar-201005:15x86
Presentationhostproxy.dll4.0.31106.099,17617-Mar-201005:15x86
Windowsbase.dll3.0.6920.50081,253,37617-Mar-201005:15x86
For all supported x64-based versions of Windows 7 and of Windows Server 2008 R2
Collapse this tableExpand this table
File nameFile versionFile sizeDateTimePlatform
Presentationcore.dll3.0.6920.50083,997,69617-Mar-201005:14x64
Presentationfontcache.exe.configNot Applicable16110-Jun-200920:30Not Applicable
Wpfgfx_v0300.dll3.0.6920.49022,255,17610-Jun-200920:30x64
Presentationframework.dll3.0.6920.50084,636,67217-Mar-201005:14x64
Presentationhostdll.dll3.0.6920.5008171,36817-Mar-201005:14x64
Presentationhost.exe4.0.31106.0320,35217-Mar-201005:14x64
Presentationhostproxy.dll4.0.31106.0109,92817-Mar-201005:14x64
Windowsbase.dll3.0.6920.50081,114,11217-Mar-201005:14x64
Presentationframework.dll3.0.6920.50085,279,74417-Mar-201005:15x64
Windowsbase.dll3.0.6920.50081,253,37617-Mar-201005:15x64

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

MORE INFORMATION

After you apply this hotfix, WPF checks only the AutomationElement objects that are measured or arranged. Additionally, this hotfix also causes WPF to build only a part of the Automation tree that contains the affected objects. Therefore, the performance of UI Automation improves.

For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:
824684 Description of the standard terminology that is used to describe Microsoft software updates

Properties

Article ID: 978520 - Last Review: October 7, 2011 - Revision: 4.0
APPLIES TO
  • Microsoft .NET Framework 3.5 Service Pack 1
Keywords: 
kbexpertiseadvanced kbsurveynew kbqfe KB978520

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