add dock layout component

crates/core/src/button.rs

@@ -40,6 +40,7 @@ pub struct Button {
     variant: ButtonVariant,
     size: Size,
     disabled: bool,
+    tab_stop: bool,
     a11y_label: Option<SharedString>,
     tooltip: Option<TooltipBuilder>,
     on_click: Option<ClickHandler>,
@@ -58,6 +59,7 @@ impl Button {
             variant: ButtonVariant::default(),
             size: Size::default(),
             disabled: false,
+            tab_stop: true,
             a11y_label: None,
             tooltip: None,
             on_click: None,
@@ -88,13 +90,19 @@ impl Button {
         self
     }
 
-    /// Sets the visual treatment.
+    /// Sets the button's visual language.
     pub fn variant(mut self, variant: ButtonVariant) -> Self {
         self.variant = variant;
         self
     }
 
-    /// Renders the button inert, unfocusable, and dimmed; disabled always wins.
+    /// Whether the button is a keyboard tab stop, dense toolbars turn it off.
+    pub fn tab_stop(mut self, tab_stop: bool) -> Self {
+        self.tab_stop = tab_stop;
+        self
+    }
+
+    /// Renders the button inert, unfocusable, and dimmed.
     pub fn disabled(mut self, disabled: bool) -> Self {
         self.disabled = disabled;
         self
@@ -193,7 +201,7 @@ impl RenderOnce for Button {
                 button
                     .cursor_pointer()
                     .focusable()
-                    .tab_stop(true)
+                    .tab_stop(self.tab_stop)
                     .hover(move |style| style.bg(hover))
                     .active(move |style| style.bg(pressed))
                     .focus_visible(|style| style.shadow(focus_ring(colors.ring)))