diff --git a/layout.lisp b/layout.lisp
index 305ef94..73ac2bc 100644
--- a/layout.lisp
+++ b/layout.lisp
@@ -23,13 +23,17 @@
          (let ((layout-tree (parent element)))
            (setf (slot-value element 'layout-tree) layout-tree)
            (setf (slot-value element 'parent) NIL)
-           (setf (root (parent element)) element)))
+           (setf (root layout-tree) element)))
         (T
          (setf (slot-value element 'layout-tree) (layout-tree (parent element)))
          (enter element (parent element)))))
 
+(defmethod print-object ((element layout-element) stream)
+  (print-unreadable-object (element stream :type T :identity T)
+    (format stream "~a" (bounds element))))
+
 (defmethod (setf bounds) ((extent extent) (element layout-element))
-  (let ((current (extent element)))
+  (let ((current (bounds element)))
     (setf (extent-x current) (extent-x extent))
     (setf (extent-y current) (extent-y extent))
     (setf (extent-w current) (extent-w extent))
@@ -37,7 +41,8 @@
     extent))
 
 (defmethod (setf bounds) :after (extent (element layout-element))
-  (notice-bounds element (parent element)))
+  (when (parent element)
+    (notice-bounds element (parent element))))
 
 (defmethod x ((element layout-element)) (extent-x (bounds element)))
 (defmethod y ((element layout-element)) (extent-y (bounds element)))
diff --git a/layouts/linear.lisp b/layouts/linear.lisp
index 86f8d32..0daa14a 100644
--- a/layouts/linear.lisp
+++ b/layouts/linear.lisp
@@ -6,7 +6,7 @@
 
 (in-package #:org.shirakumo.alloy)
 
-(defclass linear-layout (layout)
+(defclass linear-layout (layout vector-container)
   ((min-size :initarg :min-size :initform (size) :accessor min-size)
    (stretch :initarg :stretch :initform T :accessor stretch)
    (align :initarg :align :initform :start :accessor align)))
@@ -22,8 +22,9 @@
 (defmethod (setf min-size) :after (value (layout linear-layout))
   (update-linear-layout layout 0 (bounds layout)))
 
-(defmethod notice-bounds :after ((element layout-element) (layout linear-layout))
-  (let ((updated (update-linear-layout layout (element-index element layout) (bounds layout))))
+(defmethod notice-bounds ((element layout-element) (layout linear-layout))
+  ;; FIXME: optimise bounds update.
+  (let ((updated (update-linear-layout layout 0 (bounds layout))))
     (unless (extent= (bounds layout) updated)
       (setf (bounds layout) updated))))
 
diff --git a/package.lisp b/package.lisp
index f2b0ca2..f6325c3 100644
--- a/package.lisp
+++ b/package.lisp
@@ -142,6 +142,14 @@
    #:component
    #:layout
    #:layout-tree)
+  ;; layouts/fixed.lisp
+  (:export
+   #:fixed-layout)
+  ;; layouts/linear.lisp
+  (:export
+   #:linear-layout
+   #:vertical-linear-layout
+   #:horizontal-linear-layout)
   ;; renderer
   (:export
    #:allocate