Preventing applications from stealing focus

Question

Are there any solutions to prevent applications stealing focus from the active window?

This is especially annoying when I'm starting an application, switch to do something else and the new application starts receiving half a sentence of text.

Answer 1

There is an option in TweakUI which does this. It prevents most of the usual tricks dubious software developers employ to force focus on their app.

It's an ongoing arms war though, so I don't know if it works for everything.

_{Update: According to EndangeredMassa, TweakUI does not work on Windows 7.}

Answer 2

The standard way to disable applications stealing focus is to :

1. Use regedit to go to: HKEY_CURRENT_USER\Control Panel\Desktop.
2. Double-click on ForegroundLockTimeout and set its value in hexadecimal to 30d40.
3. Press OK and exit regedit.
4. Reboot your PC for the changes to take effect.

From this point forward, programs should (in theory) no longer steal the focus from the window that you're currently working in. Although this is the documented solution, it may not always work for everybody.

Another possibility is the MS-Windows focus-follows-mouse Registry hacks, where the focus and/or activation goes always to the windows under the cursor. A delay can be added to avoid applications popping up all over the desktop.
See this article : Windows 7 - Mouse Hover Makes Window Active - Enable.

[Note: From the comments below, it seems that this registry hack does not apply any more to Windows 7. So I added another answer for Windows 7.]

Answer 3

In Windows 7, the ForegroundLockTimeout registry entry is no longer checked, you can verify this with Process Monitor. In fact, in Windows 7 they disallow you from changing the foreground window. Go and read about its details, it has even been there since Windows 2000.

However, the documentation sucks and they chase each other and find ways around that.

So, there is something buggy going on with SetForegroundWindow, or similar API functions...

The only way to really do this properly is to make a small application which periodically calls LockSetForegroundWindow, virtually disabling any calls to our buggy API function.

If that's not enough (another buggy API call?) you can go even further and do some API monitoring to see what's going on, and then you simply hook the API calls on every process after which you can get rid of any calls that mess up the foreground. However, ironically, this is discouraged by Microsoft...

Answer 4

A while ago I've done extensive research on solving this issue once and for all (and failed). The result of my research can be found on the annoyance project page.

The project also includes an application that repeatedly tries to grab focus by calling:

switch( message ) {
  case WM_TIMER:
    if( hWnd != NULL ) {
      // Start off easy
      // SetForegroundWindow will not move the window to the foreground,
      // but it will invoke FlashWindow internally and, thus, show the
      // taskbar.
      SetForegroundWindow( hWnd );

      // Our application is awesome! It must have your focus!
      SetActiveWindow( hWnd );

      // Flash that button!
      FlashWindow( hWnd, TRUE );
    }
    break;

As we can see from this snippet, my research was also focused on other aspects of user interface behavior I don't like.

The way I tried to solve this was to load a DLL into every new process and hook the API calls that cause another windows to be activated.
The last part is the easy one, thanks to awesome API hooking libraries out there. I used the very great mhook library:

#include "stdafx.h"
#include "mhook-2.2/mhook-lib/mhook.h"

typedef NTSTATUS( WINAPI* PNT_QUERY_SYSTEM_INFORMATION ) ( 
  __in       SYSTEM_INFORMATION_CLASS SystemInformationClass,     
  __inout    PVOID SystemInformation, 
  __in       ULONG SystemInformationLength, 
  __out_opt  PULONG ReturnLength    
);

// Originals
PNT_QUERY_SYSTEM_INFORMATION OriginalFlashWindow   = 
  (PNT_QUERY_SYSTEM_INFORMATION)::GetProcAddress( 
  ::GetModuleHandle( L"user32" ), "FlashWindow" );

PNT_QUERY_SYSTEM_INFORMATION OriginalFlashWindowEx = 
  (PNT_QUERY_SYSTEM_INFORMATION)::GetProcAddress( 
  ::GetModuleHandle( L"user32" ), "FlashWindowEx" );

PNT_QUERY_SYSTEM_INFORMATION OriginalSetForegroundWindow = 
  (PNT_QUERY_SYSTEM_INFORMATION)::GetProcAddress( 
  ::GetModuleHandle( L"user32" ), "SetForegroundWindow" );

// Hooks
BOOL WINAPI
HookedFlashWindow(
  __in  HWND hWnd,
  __in  BOOL bInvert
  ) {
  return 0;
}

BOOL WINAPI 
HookedFlashWindowEx(
  __in  PFLASHWINFO pfwi
  ) {
  return 0;
}

BOOL WINAPI 
HookedSetForegroundWindow(
  __in  HWND hWnd
  ) {
  // Pretend window was brought to foreground
  return 1;
}


BOOL APIENTRY 
DllMain( 
  HMODULE hModule,
  DWORD   ul_reason_for_call,
  LPVOID  lpReserved
  ) {
  switch( ul_reason_for_call ) {
    case DLL_PROCESS_ATTACH:
      Mhook_SetHook( (PVOID*)&OriginalFlashWindow,         HookedFlashWindow );
      Mhook_SetHook( (PVOID*)&OriginalFlashWindowEx,       HookedFlashWindowEx );
      Mhook_SetHook( (PVOID*)&OriginalSetForegroundWindow, HookedSetForegroundWindow );
      break;

    case DLL_PROCESS_DETACH:
      Mhook_Unhook( (PVOID*)&OriginalFlashWindow );
      Mhook_Unhook( (PVOID*)&OriginalFlashWindowEx );
      Mhook_Unhook( (PVOID*)&OriginalSetForegroundWindow );
      break;
  }
  return TRUE;
}

From my tests back then, this worked great. Except for the part of loading the DLL into every new process. As one might imagine, that's nothing to take too lightly. I used the AppInit_DLLs approach back then (which is simply not sufficient).

Basically, this works great. But I never found the time to write something that properly injects my DLL into new processes. And the time invested in this largely overshadows the annoyance the focus stealing causes me.

In addition to the DLL injection problem, there is also a focus stealing method which I didn't cover in the implementation on Google Code. A co-worker actually did some additional research and covered that method. The problem was discussed on SO: http://stackoverflow.com/questions/7430864/windows-7-prevent-application-from-losing-focus

Answer 5

Ghacks has a possible solution:

It happens several times a day that some applications steal the focus of the active window by popping up. This can happen for a number of reasons, when I extract files or a transfer finishes for instance. It does not matter most of the time when this happens but sometimes I’m writing an article and it does not only mean that I have to type some words again but also that I lost concentration and have to click to regain focus.

The Pro Reviewer website has a tip on how to prevent this from happening. The easiest way of preventing focus stealing is to use Tweak UI which has a setting that is called “Prevent applications from stealing focus”. Checking this option prevents that other applications pop up suddenly and steal the focus of the window you are currently working in.

This only works when the application has been minimized before. Instead of stealing the focus it will flash a number of times which can be defined in the same menu in Tweak UI. If you do not want to use Tweak UI you can change the setting in the Windows Registry.

Navigate to the Registry key HKEY_CURRENT_USER > Control Panel > Desktop and change the ForegroundLockTimeout value to 30d40 (Hexadecimal) or 200000 (Decimal). The key ForeGroundFlashCount defines the amount of flashes of a window to alert the user where 0 means unlimited.

Answer 6

Here is another answer, since my previous answer apparently doesn't work for Windows 7.

If this is always the same application that is getting the focus, then this application is programmed to take the focus and there is no way to prevent it if the application itself doesn't provide a setting for stopping this behavior.

One idea you could try is to minimize this badly-programmed application and hope this way to disable this "feature". Or you could try to minimize it instead to the tray by using one of the free products listed in Best Free Application Minimizer.

If you do not know which application is stealing the focus, you could use the vbs script included in VB Code which identifies who's stealing focus, which the author used to identify the culprit as a "call home" updater for a printer software.

Another idea would be to fracture your desktop virtually by using a product such as Desktops or Dexpot, and to do your work in another desktop than the default.