FIX: A .NET Framework 4.0-based WPF application may stop responding if you right-click a control to open a pop-up control

Consider the following scenario:

• You run a .NET Framework 4-based Windows Presentation Foundation (WPF) application.
• Another application uses a UI Automation element to send an EVENT_OBJECT_FOCUS or EVENT_OBJECT_STATECHANGE event to the WPF application. 
• You right-click a control to open a pop-up control in the WPF application.
  
  For example, you right-click a combo box to open a pop-up menu in the WPF application.

In this scenario, the WPF application may run slowly and then stop responding.

This issue occurs because of an error in the logic that seeks the Automation peer in the UI Automation element.

Hotfix information

A supported hotfix is now available from Microsoft. However, it is intended to correct only the problem that is described in this article. Apply it only to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next that contains this hotfix.

To resolve this problem immediately, 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 website: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.

Prerequisites

To apply this hotfix, you must have the .NET Framework 4 installed.

Restart requirement

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

Hotfix replacement information

This hotfix package does not replace a previously released hotfix package.

File information

The English (United States) version of this hotfix package uses a Microsoft Windows Installer package to install the hotfix package. The dates and the times for these files are listed in Coordinated Universal Time (UTC) in the following table. When you view the file information, the date 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 XP, of Windows Server 2003, of Windows Vista, of Windows Server 2008, and of Windows 7

For all supported x64-based versions of Windows XP, of Windows Server 2003, of Windows Vista, of Windows Server 2008, of Windows 7, and of Windows Server 2008 R2

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

For more information about UI Automation, visit the following MSDN website: