clean up

src/layout/ui.rs

@@ -31,8 +31,12 @@ impl From<UI> for UIBuilder {
 }
 
 impl UIBuilder {
-    pub fn add<W: Widget>(&mut self, w: W) -> WidgetRef<W> {
-        WidgetRef::new(self.clone(), [self.push(w)])
+    pub fn add<W: Widget>(&mut self, w: impl WidgetLike<Widget = W>) -> WidgetRef<W> {
+        WidgetRef::new([w.add(self).erase_type()])
+    }
+
+    pub fn add_widget<W: Widget>(&mut self, w: W) -> WidgetRef<W> {
+        WidgetRef::new([self.push(w)])
     }
 
     pub fn push<W: Widget>(&mut self, w: W) -> WidgetId {