Setting width of select.list popup

Is there a way to set the width of a select.list() graphics popup? The popup window does not automatically resize to include all of the title

filename <- "my_long_filename.txt"

site_code <- select.list(choices = c("site_1", "site_2", "site_3", "site_4"),
                         title = paste0("Select site_code for ", filename),
                         graphics = TRUE)

It doesn’t look like it, certainly not easily. If you really want a graphical selection box, an alternative option would be shiny, where you can create custom styling via CSS.