4.8.3 ‘Hide mouse pointer when typing in window’
If you enable this option, the mouse pointer will disappear if the PuTTY window is selected and you press a key. This way, it will not obscure any of the text in the window while you work in your session. As soon as you move the mouse, the pointer will reappear.
This option is disabled by default, so the mouse pointer remains visible at all times.