Whilst Masking, I’ve accidentally drawn a red square, ( which stays there and is effecting my work area ) on the canvas. How do I remove the red square?
When would I want to use the red square if I did want to use it? What is it for?
The Red Square feature is only for die hard Communists.
Post a screen grab of the offending shape and we might be able to give you a more useful reply. 
Cheers,
R
Alright.
I’ve restarted the program this time. Let me try and make a demo-red square in a couple of hours.
Thank you for your reply.
The red square is gotten by holding down Ctrl+Shift and then releasing one of the two part-way through your drag. This is part of the partial mesh visibility feature in ZBrush.
Odds are that as you began masking you accidentally held Ctrl+Shift rather than just Ctrl. When you saw that you were getting a green rectangle, you realized that wasn’t quite right and let go of the Shift key. This changed it to a red rectangle rather than a masking rectangle.
I don’t know why the rectangle then remained. That’s not normal behavior. If you have that sort of thing happening in the future, it’ll be time to start investigating to see if one or more of your startup items is creating a problem.
Thank you Aurick for your idea.
It happened while using the lasso tool to create a mask (see screenshot)
How can I undo this type of mask? Thank you for your help.
its a stencil, in version 3 they decided it was a good idea to add this to a key combo similar to hiding, which obviously you are getting wrong(as do i when working fast), either way to turn it off when it happens just turn it off in the stencil menu.
Whoo hoo!
Thank you. This one has gotten me a few times.
I appreciate it a lot.