diff --git a/ui/containerbase.go b/ui/containerbase.go
index d528e2d..534a4b8 100644
--- a/ui/containerbase.go
+++ b/ui/containerbase.go
@@ -26,6 +26,15 @@ func (c *ContainerBase) Arrange(ctx Context, bounds geom.RectangleF32, offset ge
 	c.ControlBase.Arrange(ctx, bounds, offset, parent)
 }
 
+func (c *ContainerBase) DesiredSize(ctx Context, size geom.PointF32) geom.PointF32 {
+	var max geom.PointF32
+	for _, child := range c.Children {
+		s := child.DesiredSize(ctx, size)
+		max = geom.MaxPtF32(max, s)
+	}
+	return max
+}
+
 func (c *ContainerBase) Handle(ctx Context, e Event) bool {
 	if c.ControlBase.Handle(ctx, e) {
 		return true