Side Mouse buttons.

[SirJake]

Pretty much what I've noticed when I have forest creeps or control of other heros if afk is I can't use my back and forward mouse buttons to swap.

This is a really nice thing to be able to do when you have the forest creeps and want to use their stun or other moves.
Sure clicking the hero and putting them on hotkeys works but it's always nice to be able to swap with those fancy mouse buttons.

[Josheva]

Go into the keymapping tab, find the command you wish to assign to your buttons, click to set the hotkey, and change it to your button.

If, for any reason, this does not work, set the mouse button to something like Page Up/Page Down and map the commands to those keys.