Mouse Enter and Leave events

Mouse Enter Event
This event occurs only when the mouse collides with an object (when the mouse is over it). This object needs to have a sprite to be able to collide with the mouse.

Mouse Leave Event
This event occurs only when the mouse stops collision with an object (when the mouse is no longer over it).

Example:

You have a button object that needs to change its sprite when the mouse is over it. Then you can use the following code:

Mouse Enter event: sprite_index=spr_highlighted;

Mouse Leave event: sprite_index=spr_normal;