To reproduce:

1. Download attached project "Create-Your-Frisk.zip" and open in Unity
2. Build project with the Disclaimer scene being the first scene launched
3. Copy the "Mods" and "Default" folder from Assets to the build's folder
4. Launch the build and press Space button
5. Put any other window than Unity in front of the build, and try to scroll while hovering over the left side of the standalone, where the button list is

Expected Result: The Scroll Rect should not be scrolled
Actual Result: The Scroll Rect will be scrolled, even if the window is unfocused

Notes:
- This issue appears on Windows and Linux standalone build

Reproduced on Unity 5.6.3p3, 2017.1.1p2, 2017.2.0b11 and 2017.3.0a7