WizMouse is a Free simple and small utility developed for a small but reasonable purpose. If you install this application the scroll will work on the window under the cursor. That is it does not matter which window is on focus, so it can avoid a click to activate a screen and then scroll the mouse.
The application have few more options available
Bring the window under the mouse to foreground
reverse mouse scrolling – If you enable this feature when you scroll down, the window will scroll up.
It can enable mouse wheel support on application which does not support.
The application is available as a portable version too. So if you want to test the application you can use the portable version. I found this application really handy on the multiple monitor environment.
The application may not work with the touchpad says the developer.
Supports Windows 2000, XP, Vista, Windows 7 and Windows 8.