Bug: UIAutomation causes cumulative performance degradation in Win7 Explorer's ItemsView RRS feed

  • General discussion

  • Greetings all,

    I’ve discovered what I believe to be a fairly major bug in Windows Explorer.  This bug affects all machines running Windows 7, and as of the latest SP1 Beta that was sent out a few days ago, it is still unfixed.

    The problem is as follows: Whenever any application uses UI Automation to request Automation Elements from Explorer’s ItemsView control, the control’s responsiveness degrades slightly.  This degradation is cumulative over the lifetime of the explorer.exe process.  As more and more Automation Elements are requested, responsiveness continues to decrease, even after the application that requested the elements releases them.  This performance degradation affects the entire control, but it is most visible when scrolling through a folder with many files in it.  After about 10000 Automation Element requests, scrolling through such a folder is extremely jerky and unresponsive.  I have posted here a more detailed description of the problem, along with source code for a very simple C++ program that quickly and consistently reproduces the problem on any system running Windows 7.  The program simply requests Automation Elements and releases them, nothing else.

    UI Automation is mostly used for accessibility programs such as screen readers, but I also use it for my shell extension to ascertain information from the ItemsView control.  As such, I have a pretty big interest in seeing this bug addressed, as it does not make my extension very appealing.  What is the best way to bring this bug to Microsoft’s attention?
    • Changed type Dale Qiao Wednesday, June 30, 2010 3:12 AM
    Sunday, June 27, 2010 3:25 AM