change default text align and fix scroll drawing

src/bin/test/main.rs

@@ -121,9 +121,7 @@ impl Client {
             .span(Dir::DOWN)
             .add_static(&mut ui);
 
-        let texts = Span::empty(Dir::DOWN)
-            .gap(10)
-            .add_static(&mut ui);
+        let texts = Span::empty(Dir::DOWN).gap(10).add_static(&mut ui);
         let msg_area = texts.scroll().masked().background(rect(Color::SKY));
         let add_text = text("add")
             .editable()
@@ -190,7 +188,7 @@ impl Client {
                 .edit_on(CursorSense::HoverEnd, move |r, _| {
                     r.color = color;
                 });
-            (rect, text(label).size(30)).stack()
+            (rect, text(label).size(30).text_align(Align::CENTER)).stack()
         };
 
         let tabs = (