grid.set(gPath, newGrob, strict = FALSE, grep = FALSE, redraw = TRUE)
setGrob(gTree, gPath, newGrob, strict = FALSE, grep = FALSE)grid.set this
    specifies a grob on the display list.  For setGrob this
    specifies a descendant of the specified gTree. gPath should
    be treated as a regular expression.  Values are recycled across
    elements of the gPath (e.g., c(TRUE, FALSE) means
    that every odd element of the gPath will be treated as
    a regular expression).
  setGrob returns a grob object;  grid.set returns NULL.
setGrob copies the specified grob and returns a modified
  grob.  grid.set destructively replaces a grob on the display list.
  If redraw
  is TRUE it then redraws everything to reflect the change.
These functions should not normally be called by the user.
grid.grob.