\name{add_theme}
\alias{add_theme}
\title{Modify properties of an element in a theme object}
\usage{
  add_theme(t1, t2, t2name)
}
\arguments{
  \item{t1}{A theme object}

  \item{t2}{A theme object that is to be added to
  \code{t1}}

  \item{t2name}{A name of the t2 object. This is used for
  printing informative error messages.}
}
\description{
  Modify properties of an element in a theme object
}
\seealso{
  +.gg
}

