When you use Windows Internet Explorer 9 and later versions of Internet Explorer to view a webpage or an ActiveX control that is hosted on a webpage, the webpage or the ActiveX control may stop receiving the focus intermittently. For example, the ActiveX control may seem to be disabled, or the focus on the webpage may be in the address bar after you click the page to try to gain focus.
Note This issue can affect any user interface element on the page that can receive the focus.
This behavior occurs because the Tab window is detached from the input queue of the Frame window by design.
To work around this issue, use one of the following methods:
Avoid making long-running blocking calls or performing any synchronous work on a UI thread that can potentially interfere with the thread's message pump.
Create the following registry subkey value to disable the Hang Resistance feature:
By default, the Hang Resistance feature is enabled in Internet Explorer 9. Setting the HangRecovery value to 0 disables this feature; setting the value to 1 enables the feature.
Avoid calling the AttachThreadInput API or other APIs that can potentially result in changing the owner for the Tab window, because those APIs affect the Tab Thread's input queue. An example of an API that can change the Tab Thread's input queue is SetWindowLong.
For more information about the Hang Resistance feature in Internet Explorer 9, visit the following Microsoft website: