checkboxGroupInput with accents

I'm trying to use checkboxGroupInput in my shiny app with accents like this:

column(3,
  checkboxGroupInput("plotType", "Selecciona el estilo de la gráfica",
                     c("Líneas"="line", "Puntos"= "point"), "line")
                     )

But when I run the app the title of the checkbox is fine (where accents are present) but in the options it prints out:

Selecciona el estilo de la gráfica:

[ ] L < U + 0 0 E D > neas

[ ] Puntos

What can I do to print the accents in "Líneas" correctly???