how to remove the grid on price chart?

["Gary" <liguoyi@xxxx>]

Hi there,
 
I am a novice user. I got some questions. Please 
help to answer.
 
Is is possible to remove the grid line from AB's 
build-in price chart and other charts? I prefer to use crosshair.
 
The price is autoscaled, but the unit may be 
strange, like 0.4, etc. Can I set it to some more meaningful unit, like 0.5, 
0.25, 1, etc. Can I disable auto-scaling?
 
In function BBbandtop(C, 20, 2), period 20refers 
to simple MA or Exponential MA?
 
Thanks in advance,
 
Gary