Consider the following scenario:
You have the Microsoft .NET Framework 3.5 Service Pack 1 (SP1) installed on the computer.
You run an XAML browser application (XBAP) in a browser or in a browser tab.
You close the browser or the browser tab.
In this scenario, the PresentationHost.exe process that is associated with the XBAP application remains in memory incorrectly. Therefore, you must manually end the process in Windows Task Manager.
To resolve this issue, apply the hotfix package that is described in the following Microsoft Knowledge Base article:
2667241An update rollup is available for Windows Presentation Foundation (WPF) for Microsoft .NET Framework 3.5
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
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