After starting the computer I usually start the web browser fairly soon after start-up. Often I see the title bar flicker briefly and the colour change from Active to Inactive. The browser does not process mouse scroll or keyboard cursor messages. I need to click the browser for it to receive focus and start processing input again.

No other application is running (in the sense of having a button on the Taskbar). When I run Task Manager, nothing obvious suggests itself as the culprit. Is there any 3rd party technical tool or in-built Windows application that can identify which process is capturing focus? Presumably some Windows message like WM_SETFOCUS is involved, so perhaps there is some way to tell Windows to log any processes processing this message?

Windows 8.1


Off the top of my head, this can only be done directly with hooks. Here you can find an (unanswered) question in that direction https://stackoverflow.com/questions/29214086/how-to-catch-every-windows-setfocus-message

As mentioned in the other question, my strategy would be to have a detailed process monitor like Russinovich's ProcExp. Then when the focus is lost, press Alt+F4 to send the culprit something like WM_CLOSE. Then you will see the process close (in red) in ProcExp.


You mention that this happens at startup.

My suspicion is that a program or script starts that runs for a split second. The window for it pops up, but closes directly after. This goes so fast that you don't even see the window appear (it may even launch minimized or off-screen, but does steal focus.

My recommendation is to check what starts at startup. This can be done using msconfig.

You can disable suspected programs or scripts to see if they cause it and restart. Although you can launch the programs or scripts yourself, it may not work, as it may be that a currently running program launches this focus-stealing window and because it is still running when you execute the program/script for a second time, it may simply do nothing.

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