Event to capture unselect category - highcharts

Question

I am using highcharter library. I want to split (or filter) other charts and tables based on selection in particular category of pie (doughnut) chart. My below code is working fine.
Desired result - When user clicks on pie again after selection, it should remove filtering. Below code captures last clicked category and it matches with the current selection using curre() and lstre() reactive values.
Issue When user clicks on pie more than twice, last clicked category matches with the current selected category so it does not perform any filtering.
I tried hc_add_event_point(event = "unselect"), it does not let user select particular category of pie more than twice.
library("shiny")
library("highcharter")
library(dplyr)
ui <- shinyUI(
fluidPage(
column(width = 8, highchartOutput("hcontainer", height = "500px")),
column(width = 4, textOutput("text")),
column(width = 4, dataTableOutput('temptable')))
)
server <- function(input, output) {
a <- data.frame(b = LETTERS[1:5], c = 11:15)
aa <- data.frame(b = LETTERS[1:5])
output$hcontainer <- renderHighchart({
canvasClickFunction <- JS("function(event) {Shiny.setInputValue('canvasClicked', [this.name, event.point.name, Math.random()]);}")
legendClickFunction <- JS("function(event) {Shiny.setInputValue('legendClicked', this.name);}")
highchart() %>%
hc_chart(type="pie") %>%
hc_add_series_labels_values(labels = a$b, values = a$c,
innerSize = '60%',
allowPointSelect= TRUE,
slicedOffset = 20,
states = list(
select = list(
color= NULL,
borderWidth = 5,
borderColor = '#ccc'
))) %>%
hc_plotOptions(series = list(
events = list(click = canvasClickFunction,
legendItemClick = legendClickFunction))) %>%
hc_add_event_point(event = "unselect")
})
makeReactiveBinding("outputText")
rv <- reactiveValues(lstval=0,curval=0)
observeEvent(input$canvasClicked[2], {
rv$lstval <- rv$curval;
rv$curval <- input$canvasClicked[2]}
)
curre <- reactive({req(input$canvasClicked[2]); input$canvasClicked[2]; rv$curval})
lstre <- reactive({req(input$canvasClicked[2]); input$canvasClicked[2]; rv$lstval})
observeEvent(input$canvasClicked, {
outputText <<- paste0("You clicked on series ", input$canvasClicked[1], " and the bar you clicked was from category ", input$canvasClicked[2],
input$plot_hc_unselect, ".")
})
observeEvent(input$legendClicked, {
outputText <<- paste0("You clicked into the legend and selected series ", input$legendClicked, ".")
})
output$text <- renderText({
outputText
})
output$temptable <- renderDataTable(
if (length(input$canvasClicked[2])>0) {
if (curre()!=lstre())
aa %>% filter(b==input$canvasClicked[2])
else {
aa
}
}
else {aa}
)
}
shinyApp(ui, server)