Fill
    ---------------------
    Different to basic
     
     
    Works like BBC Basic but is not very useful in the Wimp
    environment as windows are usually partially drawn at each
    Redraw event. If By is included, the co-ordinates are relative.
     
    Use: Flood fill from [relative to] point x,y.
     
    Syntax is: Fill [By] x,y
     
    Example:
    Fill x%,y%
    Fill By dx%,dy%
     
    The Output keyword also has an effect on the Fill statement.
    Fill should be avoided if possible.
     
    For further info about Graphics in WimpBasic click here.
     
    Other keywords in the Graphics category.