geom_line() with text mapping and without group mapping doesn't render

I have a base-barchart plot with working tooltips.

I want to add a line-chart by clicking a radioButton on top of the barchart, also with hovering tooltips, which is not working as I expected.

1. When adding a text argument to the additional line, the line is not showing up, but when I hover over the pot, the labels of the line show.
2. When uncommenting the text argument (line 28), the line shows, but no hovering tooltips, as expected.
3. When removing the tooltip = "text" from the ggplotly call (line 33), the line and the tooltips shows up, but the formatting is not like I want it to be.

library(shiny)
library(ggplot2)
library(plotly)

dfN <- data.frame(
  time_stamp = seq.Date(as.Date("2018-04-01"), as.Date("2018-07-30"), 1),
  val = runif(121, 100,1000),
  col = "green", stringsAsFactors = F
)

ui <- fluidPage(
  br(),br(),
  checkboxInput("zus1", value = FALSE, label = HTML("add Line")),
  plotlyOutput("plt")
)

server <- function(input, output, session) {
  output$plt <- renderPlotly({
    key <- highlight_key(dfN)
    p <- ggplot() +
      geom_col(data = key, aes(x = plotly:::to_milliseconds(time_stamp), y = val, fill=I(col),
                               text=paste("Datum: ", time_stamp, "<br>")))
    
    
    if (input$zus1 == TRUE) {
      p <- p + geom_line(data = dfN, aes(x = plotly:::to_milliseconds(dfN$time_stamp), y = val
                                         ## This text is not showing up, but hovering shows the labels
                                         # , text=paste("Value: ", val)
                                         ), color="red")
    }
    
    ## Removing tooltip = "text" shows the additional line and hover-labels but with horrible formatting.
    ggplotly(p, source = "Src") %>% 
      highlight(selectize=F, on="plotly_click", off = "plotly_doubleclick", color = "blue") %>% 
      layout(xaxis = list(tickval = NULL, ticktext = NULL, type = "date"))
  })
}

shinyApp(ui, server)

Inizia con l’esempio Shiny fornito, concentrandoti sulla mappatura del testo di geom_line e sulla chiamata ggplotly(p) con tooltip="text". Riproduci il caso in cui la linea è nascosta ma le sue etichette vengono visualizzate, quindi determina quale comportamento fa sì che la linea e i tooltip hover formattati correttamente vengano renderizzati insieme.