I thought I had it figured it out by adding a sprite to the mouse cursor. But I need to change the opacity of the graphics, but even though I change the opacity of the sprite used as the mouse cursor, nothing happens.
Is the mouse cursor special, so you can't apply changes to the sprite used for the mouse cursor?
I found this in the manual, so it sounds kind of special.
"Set cursor from sprite
Set the cursor image from a Sprite object. This is preferable to setting a sprite to the mouse co-ordinates, because the input lag is significantly lower. Various limitations apply: the sprite image is used as it appears in the image editor, not taking in to account size or rotation in the layout; the image cannot be too large (64x64 is usually the limit); and support varies depending on browser and OS."