Only last unselect event observed by shiny

I want to implement an interaction between a DT::datatable and a highcharter scatter plot (point and row selection). When selecting multiple (2+) points in the plot (using Strg + click) and then selecting another point (without Strg + click) all points in the plot except for the last clicked are deselected and the unselect event is triggered on the javascript side. However, the shiny input that I set in the unselect event is only triggered for the last point.

Is there a possibility to change this behaviour? If not, is it possible to have multi selection without the Strg key event?

library(shiny)
library(highcharter)
library(tibble)

dt <- tibble::tibble(x = rnorm(20), y = rnorm(20),
                    id = 1:20)
ui <- fluidPage(
  shiny::fluidRow(
    highcharter::highchartOutput("foo")
  )
)

server <- function(input, output, session) {

  output$foo = highcharter::renderHighchart({

    unselectFunction <- JS("function(event) {
                               # triggers for each programmatic unselect
                               console.log('unselect: ' + this.id.toString()) 
                               Shiny.onInputChange('unselect', this.id);
                            }")

    highcharter::highchart() %>%
      hc_add_series(data    = dt,
                    type    = "scatter",
                    mapping = highcharter::hcaes(x = x, y = y)) %>%
      highcharter::hc_plotOptions(
        scatter = list(allowPointSelect = TRUE,
                       point            = list(events = list(unselect = unselectFunction))))
  })

  shiny::observeEvent(input$unselect, {
    # only triggered once (the last programmatic unselect)
  })
}

shinyApp(ui, server)

jbkunst / highcharter

Only last unselect event observed by shiny #786