The white balls are likely points that you can use to alter the position/orientation of objects and actors in your scenes (you do so by clicking them and then using the movement/rotation/enlargement tools on the bottom left of your screen).
If you want those white balls to disappear, simply go over the series of boxes on the left side of your screen and click on the box that says 'Axis' (left column, second from the bottom). To turn them back on so that you can orient things, simply click it again.
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