diff --git a/src/calc.c b/src/calc.c
index e6ebe61..0f8fe5a 100644
--- a/src/calc.c
+++ b/src/calc.c
@@ -78,12 +78,25 @@ static void adjustFont()
             fonts_get_system_font(fonts[f]));
 }
 
+static void custom_unload(Window *window)
+{
+    text_layer_destroy(s_heading_text_layer);
+
+    window_destroy(window);
+    s_custom_window = NULL;
+}
+
 /**
  * In normal token list, backspace if possible, otherwise return to script list
  * In function token list, return to normal token list
  */
 static void click_backspace(ClickRecognizerRef recognizer, void *context)
 {
+    if(s_custom_window) {
+        window_stack_remove(s_custom_window, true);
+        return;
+    }
+
     if(!using_func_tokens) {
         if(mytext[0] == '\0') {
             window_stack_remove(window_stack_get_top_window(), true);
@@ -298,14 +311,6 @@ static void custom_load(Window *window)
     window_stack_push(s_custom_window, true);
 }
 
-static void custom_unload(Window *window)
-{
-    text_layer_destroy(s_heading_text_layer);
-
-    window_destroy(window);
-    s_custom_window = NULL;
-}
-
 Object add_window(Object obj1, Object obj2, struct Environment *env)
 {
     printf("ADD_WINDOW\n");