What is Mouse 4

[$2 Hero]

[Delle(DK)]

its button 4 on your mouse IF avaliable.
It depend what kind of mouse you have and if you have a mouse 4 button you can typical configure it to what ever key you want.
Example configure mouse button 4 so that when you press it your soldier will lay down could be quite usefull.

mouse one is the left button
mouse 2 is the right button
mouse 3 is when you push down on the wheel on your mouse.
mouse 4 is on the side of the mouse
and other mouse buttons are properbly also on the left side if avaliable.
There can also be a super precission button on some products that slow down the cursor and make it very precise.

[$2 Hero]

Thanks, can I change it to 4 key instead or will I need that later? Or does it not even matter?

Yes i just thought it was weird since no game ver asked me to mouse4 before and my mouse does have side buttons which, zoom in and out etc but it wont switch to grenade.