diff --git a/box.go b/box.go
index 11e9b5a..6e39466 100644
--- a/box.go
+++ b/box.go
@@ -11,6 +11,7 @@ import "git.tebibyte.media/tomo/tomo/canvas"
 type box struct {
 	backend *Backend
 	parent   parent
+	outer    anyBox
 
 	bounds  image.Rectangle
 	minSize image.Point
@@ -45,9 +46,12 @@ type box struct {
 }
 
 func (backend *Backend) NewBox() tomo.Box {
-	return &box {
+	box := &box {
 		backend: backend,
 	}
+	box.drawer = box
+	box.outer  = box
+	return box
 }
 
 func (this *box) Box () tomo.Box {
@@ -88,10 +92,14 @@ func (this *box) SetBorder (border ...tomo.Border) {
 }
 
 func (this *box) SetMinimumSize (width, height int) {
-	this.minSize = image.Pt(width, height)
+	minSize := image.Pt(width, height)
+	if this.minSize == minSize { return }
+	this.minSize = minSize
+	
 	if this.bounds.Dx() < width || this.bounds.Dy() < height {
 		this.invalidateLayout()
 	}
+	// TODO: alert the parent
 }
 
 func (this *box) SetPadding (padding tomo.Inset) {
@@ -112,7 +120,7 @@ func (this *box) SetFocused (focused bool) {
 	if this.Focused () && !focused {
 		this.parent.window().focus(nil)
 	} else if !this.Focused() && focused {
-		this.parent.window().focus(this)
+		this.parent.window().focus(this.outer)
 	}
 }
 
@@ -125,7 +133,7 @@ func (this *box) SetFocusable (focusable bool) {
 }
 
 func (this *box) Focused () bool {
-	return this == this.parent.window().focused
+	return this.outer == this.parent.window().focused
 }
 
 func (this *box) Modifiers () input.Modifiers {
@@ -136,7 +144,7 @@ func (this *box) MousePosition () image.Point {
 	return this.parent.window().mousePosition
 }
 
-// ----- event handlers ----------------------------------------------------- //
+// ----- event handler setters ---------------------------------------------- //
 func (this *box) OnFocusEnter (callback func()) event.Cookie {
 	return this.on.focusEnter.Connect(callback)
 }
@@ -179,8 +187,14 @@ func (this *box) OnKeyUp (callback func(key input.Key, numberPad bool)) event.Co
 // -------------------------------------------------------------------------- //
 
 func (this *box) Draw (can canvas.Canvas) {
+	this.drawBorders(can)
 	pen := can.Pen()
+	pen.Fill(this.color)
+	pen.Rectangle(this.bounds)
+}
 
+func (this *box) drawBorders (can canvas.Canvas) {
+	pen := can.Pen()
 	bounds := this.bounds
 	for _, border := range this.border {
 		pen.Fill(border.Color[tomo.SideTop])
@@ -210,15 +224,11 @@ func (this *box) Draw (can canvas.Canvas) {
 
 		bounds = border.Width.Apply(bounds)
 	}
-	pen.Fill(this.color)
-	pen.Rectangle(bounds)
 }
 
 func (this *box) doDraw () {
 	if this.canvas == nil { return }
-	if this.drawer == nil {
-		this.Draw(this.canvas)
-	} else {
+	if this.drawer != nil {
 		this.drawer.Draw(this.canvas)
 	}
 }
@@ -236,12 +246,12 @@ func (this *box) recursiveRedo () {
 	this.doDraw()
 }
 
-func (this *box) invalidateDraw () {
-	if this.parent == nil { return }
-	this.parent.window().invalidateDraw(this)
+func (this *box) invalidateLayout () {
+	if this.parent == nil || this.parent.window() == nil { return }
+	this.parent.window().invalidateLayout(this.outer)
 }
 
-func (this *box) invalidateLayout () {
-	if this.parent == nil { return }
-	this.parent.window().invalidateLayout(this)
+func (this *box) invalidateDraw () {
+	if this.parent == nil || this.parent.window() == nil { return }
+	this.parent.window().invalidateDraw(this.outer)
 }
diff --git a/canvasbox.go b/canvasbox.go
index 1ccb038..fcabfb8 100644
--- a/canvasbox.go
+++ b/canvasbox.go
@@ -8,9 +8,11 @@ type canvasBox struct {
 }
 
 func (backend *Backend) NewCanvasBox () tomo.CanvasBox {
-	return &canvasBox {
+	box := &canvasBox {
 		box: backend.NewBox().(*box),
 	}
+	box.outer = box
+	return box
 }
 
 func (this *canvasBox) Box () tomo.Box {
diff --git a/containerbox.go b/containerbox.go
index 525c187..9f1123a 100644
--- a/containerbox.go
+++ b/containerbox.go
@@ -1,8 +1,176 @@
 package x
 
+import "image"
+import "image/color"
 import "git.tebibyte.media/tomo/tomo"
+import "git.tebibyte.media/tomo/tomo/event"
+import "git.tebibyte.media/tomo/tomo/canvas"
+
+type containerBox struct {
+	*box
+
+	hOverflow, vOverflow bool
+	contentBounds image.Rectangle
+	scroll        image.Point
+	
+	gap      tomo.Gap
+	children []anyBox
+	layout   tomo.Layout
+
+	on struct {
+		contentBoundsChange event.FuncBroadcaster
+	}
+}
 
 func (backend *Backend) NewContainerBox() tomo.ContainerBox {
-	// TODO
-	return nil
+	box := &containerBox {
+		box: backend.NewBox().(*box),
+	}
+	box.drawer = box
+	box.outer  = box
+	return box
+}
+
+func (this *containerBox) Box () tomo.Box {
+	return this
+}
+
+func (this *containerBox) SetOverflow (horizontal, vertical bool) {
+	if this.hOverflow == horizontal && this.vOverflow == vertical { return }
+	this.hOverflow = horizontal
+	this.vOverflow = vertical
+	this.invalidateLayout()
+}
+
+func (this *containerBox) ContentBounds () image.Rectangle {
+	return this.contentBounds
+}
+
+func (this *containerBox) ScrollTo (point image.Point) {
+	// TODO: constrain scroll
+	this.scroll = point
+	this.invalidateLayout()
+}
+
+func (this *containerBox) OnContentBoundsChange (callback func()) event.Cookie {
+	return this.on.contentBoundsChange.Connect(callback)
+}
+
+func (this *containerBox) SetGap (gap tomo.Gap) {
+	if this.gap == gap { return }
+	this.gap = gap
+	this.invalidateLayout()
+}
+
+func (this *containerBox) Add (child tomo.Object) {
+	box := assertAnyBox(child.Box())
+	if indexOf(this.children, box) > -1 { return }
+	
+	box.setParent(this)
+	this.children = append(this.children, box)
+	this.invalidateLayout()
+}
+
+func (this *containerBox) Delete (child tomo.Object) {
+	box := assertAnyBox(child.Box())
+	index := indexOf(this.children, box)
+	if index < 0 { return }
+	
+	box.setParent(nil)
+	this.children = remove(this.children, index)
+	this.invalidateLayout()
+}
+
+func (this *containerBox) Insert (child, before tomo.Object) {
+	box := assertAnyBox(child.Box())
+	if indexOf(this.children, box) > -1 { return }
+
+	beforeBox := assertAnyBox(before.Box())
+	index     := indexOf(this.children, beforeBox)
+	if index < 0 { return }
+	
+	box.setParent(this)
+	this.children = insert(this.children, index, box)
+	this.invalidateLayout()
+}
+
+func (this *containerBox) Clear () {
+	for _, box := range this.children {
+		box.setParent(nil)
+	}
+	this.children = nil
+	this.invalidateLayout()
+}
+
+func (this *containerBox) Length () int {
+	return len(this.children)
+}
+
+func (this *containerBox) At (index int) tomo.Object {
+	if index < 0 || index >= len(this.children) {
+		return nil
+	}
+	return this.children[index]
+}
+
+func (this *containerBox) SetLayout (layout tomo.Layout) {
+	this.layout = layout
+	this.invalidateLayout()
+}
+
+func (this *containerBox) Draw (can canvas.Canvas) {
+	this.drawBorders(can)
+	pen := can.Pen()
+	pen.Fill(this.color)
+
+	// TODO: do this in doLayout and save the result
+	rocks := make([]image.Rectangle, len(this.children))
+	for index, box := range this.children {
+		rocks[index] = box.Bounds()
+	}
+	// TODO: use shatter algorithm here to optimize amount of pixels drawn
+	// and not draw over child boxes
+	for index, tile := range canvas.Shatter(this.bounds, rocks...) {
+		pen.Fill(color.RGBA { R: uint8(32 * (index + 2)), A: 255 })
+		pen.Rectangle(tile)
+	}
+}
+
+func (this *containerBox) window () *window {
+	if this.parent == nil { return nil }
+	return this.parent.window()
+}
+
+func (this *containerBox) canvas () canvas.Canvas {
+	return this.box.canvas
+}
+
+func (this *containerBox) doLayout () {
+	this.box.doLayout()
+	// TODO: possibly store all children as tomo.Box-es and don't allocate a
+	// slice here
+	previousContentBounds := this.contentBounds
+	boxes := make([]tomo.Box, len(this.children))
+	for index, box := range this.children {
+		boxes[index] = box
+	}
+	if this.layout != nil {
+		// TODO maybe we should pass more information into Arrange such
+		// as overflow information and scroll
+		this.layout.Arrange (
+			this.InnerBounds().Sub(this.scroll),
+			this.gap,
+			boxes)
+	}
+	if previousContentBounds != this.contentBounds {
+		this.on.contentBoundsChange.Broadcast()
+	}
+}
+
+func (this *containerBox) recursiveRedo () {
+	this.doLayout()
+	this.doDraw()
+	for _, child := range this.children {
+		child.recursiveRedo()
+	}
 }
diff --git a/go.mod b/go.mod
index 1f1ee10..4674fec 100644
--- a/go.mod
+++ b/go.mod
@@ -4,7 +4,7 @@ go 1.20
 
 require (
 	git.tebibyte.media/tomo/ggfx v0.3.0
-	git.tebibyte.media/tomo/tomo v0.7.3
+	git.tebibyte.media/tomo/tomo v0.8.0
 	git.tebibyte.media/tomo/xgbkb v1.0.1
 	github.com/jezek/xgb v1.1.0
 	github.com/jezek/xgbutil v0.0.0-20230603163917-04188eb39cf0
diff --git a/go.sum b/go.sum
index 38f7759..1b663d0 100644
--- a/go.sum
+++ b/go.sum
@@ -21,6 +21,8 @@ git.tebibyte.media/tomo/tomo v0.7.2 h1:15dMJm4Sm339b23o9RZSq87u99SaF2q+b5CRB5P58
 git.tebibyte.media/tomo/tomo v0.7.2/go.mod h1:lTwjpiHbP4UN/kFw+6FwhG600B+PMKVtMOr7wpd5IUY=
 git.tebibyte.media/tomo/tomo v0.7.3 h1:eHwuYKe+0nLWoEfPZid8njirxmWY3dFmdY+PsPp1RN0=
 git.tebibyte.media/tomo/tomo v0.7.3/go.mod h1:lTwjpiHbP4UN/kFw+6FwhG600B+PMKVtMOr7wpd5IUY=
+git.tebibyte.media/tomo/tomo v0.8.0 h1:Sqvos2Huf0mSHFZ0FJrBZiH8Ro/gmQPHCvK6Qr29SBo=
+git.tebibyte.media/tomo/tomo v0.8.0/go.mod h1:lTwjpiHbP4UN/kFw+6FwhG600B+PMKVtMOr7wpd5IUY=
 git.tebibyte.media/tomo/xgbkb v1.0.1 h1:b3HDUopjdQp1MZrb5Vpil4bOtk3NnNXtfQW27Blw2kE=
 git.tebibyte.media/tomo/xgbkb v1.0.1/go.mod h1:P5Du0yo5hUsojchW08t+Mds0XPIJXwMi733ZfklzjRw=
 github.com/BurntSushi/freetype-go v0.0.0-20160129220410-b763ddbfe298 h1:1qlsVAQJXZHsaM8b6OLVo6muQUQd4CwkH/D3fnnbHXA=
diff --git a/system.go b/system.go
index 9d1aef6..83cf00b 100644
--- a/system.go
+++ b/system.go
@@ -44,6 +44,14 @@ type anyBox interface {
 	recursiveRedo ()
 }
 
+func assertAnyBox (unknown tomo.Box) anyBox {
+	if box, ok := unknown.(anyBox); ok {
+		return box
+	} else {
+		panic("foregin box implementation, i did not make this!")
+	}
+}
+
 func (window *window) SetRoot (root tomo.Object) {
 	if window.root != nil {
 		window.root.setParent(nil)
@@ -51,7 +59,7 @@ func (window *window) SetRoot (root tomo.Object) {
 	if root == nil {
 		window.root = nil
 	} else {
-		box := root.Box().(anyBox)
+		box := assertAnyBox(root.Box())
 		box.setParent(window)
 		window.invalidateLayout(box)
 		window.root = box
diff --git a/util.go b/util.go
new file mode 100644
index 0000000..86e1143
--- /dev/null
+++ b/util.go
@@ -0,0 +1,20 @@
+package x
+
+func indexOf[T comparable] (haystack []T, needle T) int {
+	for index, test := range haystack {
+		if test == needle {
+			return index
+		}
+	}
+	return -1
+}
+
+func remove[T any] (slice []T, index int) []T {
+	return append(slice[:index], slice[index + 1:]...)
+}
+
+func insert[T any] (slice []T, index int, element T) []T {
+	slice = append(slice[:index + 1], slice[index:]...)
+	slice[index] = element
+	return slice
+}