MouseMAC

MouseMAC is an intuitive piece of software that brings Mac functionality to Windows computers, giving you the possibility to scroll pages with the mouse on windows that aren't currently selected. This is particularly useful when working with multiple opened windows, so you don't have to make windows active and lose the pointer position from the previous window.

Enable mouse scrolling on inactive windows

Although this application works even with newer Windows editions, the mouse scrolling feature is built into in the operating system and should be enabled. If it's not, it can be easily resolved with a registry tweak. However, if you don't want to risk modifying important registry entries by accident, then you can turn to this lightweight utility instead.

Portable mouse tweaker that runs in the systray

MouseMAC doesn't require installation. It's wrapped in a single .exe file that can be dropped anywhere on the disk and just double-clicked to launch the program. You can also save it to a USB flash drive to run it on all your devices without setup and enable the mouse scrolling functionality over inactive windows.
The mouse tweaker gets integrated into the system tray at startup and runs in the background without disturbing you with notifications. As soon as it's deployed, you can test the tool by opening two windows side by side, clicking a window to make it active, moving the cursor to the inactive window without clicking it, and using the scrollwheel. As you can see, no configuration or additional actions are necessary after running the program.

Invert mouse scrolling effortlessly

On the other hand, MouseMAC has one more nifty feature prepared: inverting the scrolling so that scrolling up makes the page go down, and vice versa. Note that these effects return to normal automatically after exiting the utility. However, you can disable it from the systray menu without quitting to the desktop, as well as instruct it to autorun at every Windows startup and to enable/disable listbox smooth scrolling (via the right-click menu).
All aspects considered, MouseMAC is a practical mouse tweaking application, especially for older Windows versions which don't have built-in functionality for scrolling on inactive windows. Nevertheless, it works smoothly even on newer Windows and brings scrolling inversion to the table.