diff --git a/main/scenes/scene_bootanim.c b/main/scenes/scene_bootanim.c
index edc0ae1..98fa0ce 100644
--- a/main/scenes/scene_bootanim.c
+++ b/main/scenes/scene_bootanim.c
@@ -5,7 +5,7 @@
 #include "liquid.h"
 #include "graphics/drawing.h"
 
-#define BOOTANIM_TIME_MS 100
+#define BOOTANIM_TIME_MS 2000
 
 struct BootScene {
     struct Scene base;
diff --git a/main/scenes/scene_menu.c b/main/scenes/scene_menu.c
index 17a5eb8..1f556be 100644
--- a/main/scenes/scene_menu.c
+++ b/main/scenes/scene_menu.c
@@ -59,6 +59,11 @@ static void deinit(struct MenuScene *self)
 {
     free(self->items);
     self->items = NULL;
+
+    if (self->extra_deinit) {
+        self->extra_deinit((struct Scene *) self);
+        self->extra = NULL;
+    }
 }
 
 struct MenuScene *NewScene_Menu(struct MenuItem *items, size_t items_len) {
@@ -68,6 +73,10 @@ struct MenuScene *NewScene_Menu(struct MenuItem *items, size_t items_len) {
     scene->base.onInput = (Scene_onInput_t) onInput;
     scene->base.deinit = (Scene_deinit_t) deinit;
 
+    // onChildReturn is free to set by subclass
+
+    // TODO long selected label scrolling on tick
+
     scene->items = items;
     scene->items_len = items_len;
 
diff --git a/main/scenes/scene_menu.h b/main/scenes/scene_menu.h
index c649c1d..5a44f75 100644
--- a/main/scenes/scene_menu.h
+++ b/main/scenes/scene_menu.h
@@ -1,5 +1,5 @@
 /**
- * TODO file description
+ * Scrollable menu
  * 
  * Created on 2020/01/05.
  */
@@ -12,13 +12,26 @@
 
 #define MENUITEM_LABEL_LEN 30
 
+/**
+ * One item of the menu
+ */
 struct MenuItem {
+    // menu label
     char label[MENUITEM_LABEL_LEN];
+    // item tag (useful with dynamically generated menus)
     uint32_t tag;
 };
 
 struct MenuScene;
 
+/**
+ * Selection handler.
+ *
+ * When an item is selected, this abstract method is fired to determine what should happen.
+ *
+ * The selected item is available as scene.selected.
+ * Return SceneEvent to take, e.g. to close the menu, or to open a sub-scene.
+ */
 typedef struct SceneEvent (*MenuScene_onSelect_t)(struct MenuScene *scene);
 
 struct MenuScene {
@@ -33,10 +46,21 @@ struct MenuScene {
     int32_t selected;
     // selection handler
     MenuScene_onSelect_t onSelect;
-    // Extra field for the instance's private use.
-    void *private;
+    // Extra field for the subclass's private use.
+    void *extra;
+    // fp for extra's deinit function
+    Scene_deinit_t extra_deinit;
 };
 
+/**
+ * Create a new items menu.
+ *
+ * This is normally called from a subclass.
+ *
+ * @param items - menu items on heap (the MenuScene will free them on close)
+ * @param items_len - item count
+ * @return the menu
+ */
 struct MenuScene *NewScene_Menu(struct MenuItem *items, size_t items_len);
 
 #endif //REFLOWER_SCENE_MENU_H
diff --git a/main/scenes/scene_number.c b/main/scenes/scene_number.c
index 058d86a..1e7fd14 100644
--- a/main/scenes/scene_number.c
+++ b/main/scenes/scene_number.c
@@ -1,8 +1,7 @@
-#include "scenes.h"
-#include "liquid.h"
 #include <malloc.h>
 #include <stdio.h>
-#include "graphics/nokia.h"
+#include "scenes.h"
+#include "liquid.h"
 #include "graphics/drawing.h"
 #include "scene_number.h"
 
diff --git a/main/scenes/scene_number.h b/main/scenes/scene_number.h
index a215cf8..3e37e4e 100644
--- a/main/scenes/scene_number.h
+++ b/main/scenes/scene_number.h
@@ -9,20 +9,27 @@
 
 #include <stdint.h>
 
+/**
+ * Options passed to the NumberScene constructor
+ */
 struct NumberSceneOpts {
+    // Screen title
     char label[15];
+    // Unit added to the value
     char unit[8];
+    // Initial value
     int32_t value;
+    // min value
     int32_t min;
+    // max value
     int32_t max;
 };
 
 /**
  * Create number picker.
  *
- * The result is passed back as status.
- *
  * "opts" must be on heap and will be internally mutated.
+ * The scene frees them on exit, returning the selected value as status.
  *
  * @param opts
  * @return
diff --git a/main/scenes/scene_test_menu.c b/main/scenes/scene_test_menu.c
index 8602f82..e487ef0 100644
--- a/main/scenes/scene_test_menu.c
+++ b/main/scenes/scene_test_menu.c
@@ -12,11 +12,10 @@
 
 struct Priv {
     int32_t number;
-    Scene_deinit_t parent_deinit;
 };
 
 static struct SceneEvent onSelect(struct MenuScene *self) {
-    struct Priv *priv = self->private;
+    struct Priv *priv = self->extra;
 
     if (self->selected == 0) {
         return SceneEvent_Close(0, NULL);
@@ -46,19 +45,15 @@ static struct SceneEvent onSelect(struct MenuScene *self) {
     return SceneEvent_None();
 }
 
-static void deinit(struct MenuScene *self)
+static void priv_deinit(struct MenuScene *self)
 {
-    struct Priv *priv = self->private;
-    if (priv->parent_deinit) {
-        priv->parent_deinit((struct Scene *) self);
-    }
-    free(self->private);
-    self->private = NULL;
+    free(self->extra);
+    self->extra = NULL;
 }
 
 static struct SceneEvent onChildReturn(struct MenuScene *self, uint32_t tag, int32_t status, void *data)
 {
-    struct Priv *priv = self->private;
+    struct Priv *priv = self->extra;
     if (tag == 99) {
         priv->number = status;
         snprintf(self->items[2].label, MENUITEM_LABEL_LEN, "Set=%d°C", priv->number);
@@ -88,10 +83,10 @@ struct Scene *NewScene_MenuTest() {
     // private data added by the subclass
     struct Priv *priv = calloc(1, sizeof(struct Priv));
     priv->number = 0;
-    priv->parent_deinit = scene->base.deinit;
-    scene->private = priv;
+    scene->extra = priv;
+    scene->extra_deinit = (Scene_deinit_t) priv_deinit;
 
-    scene->base.deinit = (Scene_deinit_t) deinit;
+    // add a child return handler (base does not use this)
     scene->base.onChildReturn = (Scene_onChildReturn_t) onChildReturn;
 
     return (struct Scene *) scene;