Finally, include the forestplot R package and call the forestplot function with appropriate arguments. The way I got around to creating the horizontal band at every alternate row was by using settings for a very thick transparent line in the hrzl_lines argument! See below. The col="#99999922″ option gives the light grey color to the line as. 2022. 7. 26. · Details. This function obsoletes fpColors . If some, but not all parameters of a shape (e.g. box) are specified in gpar () such as setting lwd but not line color, the unspecified parameters default to the ones specified in default, then, default to legacy parameters of forestplot such as col . Parameters box, lines, vertices, summary may be set.