You probably copied one of the examples that create a hover icon using an event active area in the onBeforeEventRender
event handler.
It might look like this:
onBeforeEventRender: args => {
args.data.areas = [
{
right: 5,
top: 5,
height: 20,
width: 20,
visibility: "Hover",
// ...
]
}
You will need to remove it to get rid of the box.