diff --git a/R/gadget.R b/R/gadget.R
index bbbeb04..f890b10 100644
--- a/R/gadget.R
+++ b/R/gadget.R
@@ -1,6 +1,6 @@
 .pal <- function() {
   pal_fn <- .pal_app()
-  if (identical(pal_fn, "rs_pal_")) {
+  if (is.null(pal_fn) || identical(pal_fn, "rs_pal_")) {
     return(NULL)
   }
   try_fetch(
@@ -41,6 +41,9 @@
     shiny::observeEvent(input$done, {
       shiny::stopApp(returnValue = paste0("rs_pal_", input$pal))
     })
+    shiny::onStop(function() {
+      shiny::stopApp(returnValue = NULL)
+    })
   }
 
   viewer <- shiny::dialogViewer("Pal", width = 300, height = 10)