When I go to configure my mouse button controls the mouse buttons only go up to 3 rendering all others useless

I expected it to continue on to mouse button 4, 5 and so on when I clicked those buttons on my mouse

What actually happened was it went up to 3 and all other buttons stayed at 3

Steps to Reproduce
1. Go to settings
2. Click on any control
3. Use any mouse button besides your main 3