By default Windows XP automatically prevents an application from stealing focus. You have probably already noticed this when you have had a number of applications minimised to the taskbar and one particular application has wanted you attention so the tab of the minimised application starts flashing orange. However, there have been cases where the minimised application tab refuses to flash orange when the application has attempted to grab focus. This is because an application you have installed has disabled the prevent an application from stealing focus option. To remedy the problem proceed as follows.
The first, and perhaps the easiest, root is to attempt a System Restore back to a point when you had full functionality of the flashing taskbar tab. In most cases this will remedy the problem.
If this option fails then the next easiest option is to download the Microsoft Powertoy TweakUI, available from: (http://www.microsoft.com/windowsxp/downloads/powertoys/xppowertoys.mspx) Click the + sign next to the General option and then click on Focus. Now make sure a tick is in the box marked Prevent applications from stealing focus.
If that option fails you can always try editing the Windows registry.
For safety reasons it is always advisable to backup the registry before you start editing it. While there are numerous third party application that will do this for you, i.e., ERUNT, you can just as easily backup the registry using Windows XP.
1/ Click the Start button.
2/ From the Start Menu click Run.
3/ In the Run dialogue box type regedit.
4/ When the registry window opens navigate to the following Registry key: HKEY_CURRENT_USER/ControlPanel/Desktop
5/ Click on the Desktop option and then look down the list on the right for the following: foregroundlocktimeout.
6/ The right hand list is divided into three sections:
7/ Look in the Data section and check that the following is present:
8/ If this data is present then the Prevent applications from stealing focus option is enabled.
9/ If you have something different then proceed as follows:
10/ Right click on the ForegroundLockTimeout option and select Modify.
11/ The Edit DWORD value box opens.
12/ Make sure there is a dot next to the hexadecimal option in the Base box.
13/ Now in the Value data box type: 30d40 (that's thirty followed by d then followed by 40).
14/ Click the OK button
15/ Your entry should now read:
ForegroundLockTimeout REG_DWORD 0x00030d40 (200000)
16/ Now close regedit and reboot your machine.