diff --git a/internal/system/hierarchy.go b/internal/system/hierarchy.go
index 26d30a0..2224ce4 100644
--- a/internal/system/hierarchy.go
+++ b/internal/system/hierarchy.go
@@ -86,6 +86,47 @@ func (this *Hierarchy) MinimumSize () image.Point {
 	return this.minimumSize
 }
 
+// AfterEvent should be called at the end of every event cycle.
+func (this *Hierarchy) AfterEvent () {
+	if this.canvas == nil { return }
+
+	if this.needRedo {
+		// set child bounds
+		childBounds := this.canvas.Bounds()
+		childBounds = childBounds.Sub(childBounds.Min)
+		if this.root != nil {
+			this.root.SetBounds(childBounds)	
+		}
+
+		// full relayout/redraw
+		if this.root != nil {
+			this.root.recursiveRedo()
+		}
+		this.link.PushAll()
+		this.needRedo = false
+		return
+	}
+
+	for len(this.needMinimum) > 0 {
+		this.needMinimum.Pop().doMinimumSize()
+	}
+	if !this.minimumClean {
+		this.doMinimumSize()
+	}
+	for len(this.needLayout) > 0 {
+		this.needLayout.Pop().doLayout()
+	}
+	var toPush image.Rectangle
+	for len(this.needDraw) > 0 {
+		box := this.needDraw.Pop()
+		box.doDraw()
+		toPush = toPush.Union(box.Bounds())
+	}
+	if !toPush.Empty() {
+		this.link.PushRegion(toPush)
+	}
+}
+
 func (this *Hierarchy) getHierarchy () *Hierarchy {
 	return this
 }
@@ -231,46 +272,6 @@ func (this *Hierarchy) propagateAlt (callback func (box anyBox) bool) {
 	this.root.propagateAlt(callback)
 }
 
-func (this *Hierarchy) afterEvent () {
-	if this.canvas == nil { return }
-
-	if this.needRedo {
-		// set child bounds
-		childBounds := this.canvas.Bounds()
-		childBounds = childBounds.Sub(childBounds.Min)
-		if this.root != nil {
-			this.root.SetBounds(childBounds)	
-		}
-
-		// full relayout/redraw
-		if this.root != nil {
-			this.root.recursiveRedo()
-		}
-		this.link.PushAll()
-		this.needRedo = false
-		return
-	}
-
-	for len(this.needMinimum) > 0 {
-		this.needMinimum.Pop().doMinimumSize()
-	}
-	if !this.minimumClean {
-		this.doMinimumSize()
-	}
-	for len(this.needLayout) > 0 {
-		this.needLayout.Pop().doLayout()
-	}
-	var toPush image.Rectangle
-	for len(this.needDraw) > 0 {
-		box := this.needDraw.Pop()
-		box.doDraw()
-		toPush = toPush.Union(box.Bounds())
-	}
-	if !toPush.Empty() {
-		this.link.PushRegion(toPush)
-	}
-}
-
 func (this *Hierarchy) drawBackgroundPart (canvas.Canvas) {
 	// TODO
 	// no-op for now? maybe eventually windows will be able to have a