Thats the brush overlay. Hit the O key to toggle it on and off
Allen Fishman, M.D.
Sent from my iPhone
there is a box to that can be ticked under the image when the bush is selected
if is not there then hit "T" to open the small panel under the image
if you cannot find the dots/buttons for each use of a tool then hit "H". Tool need to be active btw
SHIFT+O will toggle through the available colors of the mask overlay- Red, Green, Grey, Clear.
Useful if you cannot see the Red overlay on a red subject- press- Shift+O.