Unselect map area by clicking it again

server.R

@@ -96,6 +96,14 @@ server <- function(input, output, session) {
     click_event <- input$hhmap_shape_click
     # Check if an ID was returned (meaning a polygon was clicked)
     if (!is.null(click_event$id)) {
+      if(click_event$group == "selected") {
+        # Clicked on an already selected area of the map therefore we unselect.
+        currently_selected_bezirk("")
+        currently_selected_stadtteil("")
+        leafletProxy("hhmap") %>%
+          clearGroup("selected")
+        return()
+      }
       
       # The ID of the clicked polygon
       clicked_polygon_id <- click_event$id