clear (or just c)
Issued without parameters, the clear command does pretty
heavy duty clearing of many of the GrADS internal settings. Parameters
can be added to limit what is cleared when using more advanced
features.
WARNING: If you make any error in the syntax of clear
then GrADS does the full clear
c norset clears without resetting user options
c events flushes the events buffer (e.g., mouse clicks)
c graphics clears the graphics, but not the widgets
c hbuff clears
the display buffer when in double buffer mode
c button num clears button num
c rband num clears rband num
c dropmenu num clears dropmenu num
c sdfwrite clears sdfwrite file name and attributes without resetting other user options