Sets ForegroundLockTimeout = 0 under HKCU\Control Panel\Desktop. Windows normally blocks a background app from stealing foreground for ~200 ms after you interact elsewhere, which is what causes a game to sometimes minimise-then-not-refocus on Alt-Tab, or a launched app to open behind your current window. Zeroing it lets the requested window come to the front immediately. Takes effect on next sign-in. Reversible.
MaxTweaks applies this tweak with one click and snapshots your original setting first, so you can revert it cleanly at any time. A System Restore point is offered before batch changes, and every tweak links to its official source.
Get MaxTweaksOfficial documentation: https://learn.microsoft.com/en-us/windows/win32/sysinfo/control-panel-desktop-keys