The following program sets the background and foreground borders and default colors to blue and yellow, respectively.

Open #1,{"","titl,hide",40,10} As "Window" 

! Hidden Window

Print #1;'255Backcolor cs ye'; 

! set border and default colors

Channel 11,#1; 

! make window visible 

After the Channel statement, the current foreground and background colors may be changed to desired colors without affecting the border colors.