Dave, thanks very much for pursuing this. Further experimentation shows me that the phantom rectangle does indeed happen on click, not hover, I was wrong about that. Also it occurs when a brush (or tool) with a Bristle tip is used and carries on when a brush tip is then changed in the brush attributes palette for an ordinary brush like a Spatter. If you then select a different tool, and then go back to the brush with the ordinary brush tip, the rectangle does not reappear. It must be some strange action of a bristle tip brush. I wonder what the two vertical lines of small white dots at the top left of the rectangle signify? David
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