proper widgetid + slot vec instead of map

core/src/widget/mod.rs

@@ -27,6 +27,16 @@ impl Widget for () {
     }
 }
 
+impl dyn Widget {
+    pub fn as_any(&self) -> &dyn Any {
+        self
+    }
+
+    pub fn as_any_mut(&mut self) -> &mut dyn Any {
+        self
+    }
+}
+
 /// A function that returns a widget given a UI.
 /// Useful for defining trait functions on widgets that create a parent widget so that the children
 /// don't need to be IDs yet