Do not overwrite panel's 'ylim' value

This was overwriting the panel's 'ylim' value with the value for
'ylim_render', when the value for 'ylim' should be as read-only.

R/plot.R

@@ -1227,12 +1227,14 @@ new.replot_xts <- function(panel=1,asp=1,xlim=c(1,10),ylim=list(structure(c(1,10
 
  if (use_global_ylim) {
  # use the ylim based on all panels' data
- ylim <- ylim_render
+ yl <- ylim_render
+ } else {
+ yl <- ylim
  }
 
- # y-axis grid line locations
- grid_loc <- pretty(ylim, Env$yaxis.ticks)
- grid_loc <- grid_loc[grid_loc >= ylim[1] & grid_loc <= ylim[2]]
+ # y-axis grid line labels and locations
+ grid_loc <- pretty(yl, Env$yaxis.ticks)
+ grid_loc <- grid_loc[grid_loc >= yl[1] & grid_loc <= yl[2]]
 
  # draw y-axis grid lines
  segments(x0 = xlim[1], y0 = grid_loc,