T07b navigation places: nav item and group, navigation menu, back and forward history, table of contents with anchors, go to line; measuring canvases pinned to their parent

src/forms/slider.rs

@@ -205,6 +205,8 @@ impl Track {
                     |_, _, _, _| {},
                 )
                 .absolute()
+                .top_0()
+                .left_0()
                 .size_full(),
             )
             .when(!self.disabled, |inner| {