diff --git a/ui/length.go b/ui/length.go
index d6f23b5..b1bba29 100644
--- a/ui/length.go
+++ b/ui/length.go
@@ -13,11 +13,11 @@ func (l *Length) Value() float32 {
 	return l.float32
 }
 
-func (l *Length) Zero(value float32) *Length {
+func (l *Length) Zero(value float32) float32 {
 	if l == nil {
-		return &Length{value}
+		return value
 	}
-	return l
+	return l.Value()
 }
 
 func Fixed(l float32) *Length { return &Length{l} }
diff --git a/ui/spacing.go b/ui/spacing.go
index 3309c57..93ec626 100644
--- a/ui/spacing.go
+++ b/ui/spacing.go
@@ -70,7 +70,7 @@ func addMargin(bounds geom.PointF32, size geom.PointF32, margin SideLengths) geo
 func (s *Spacing) Arrange(ctx Context, bounds geom.RectangleF32, offset geom.PointF32) {
 	var size = s.Proxy.DesiredSize(ctx)
 	var w, h = s.Width.Zero(size.X), s.Height.Zero(size.Y)
-	var content = addMargin(geom.PtF32(bounds.Dx(), bounds.Dy()), geom.PtF32(w.Value(), h.Value()), s.Margin).Add(bounds.Min)
+	var content = addMargin(geom.PtF32(bounds.Dx(), bounds.Dy()), geom.PtF32(w, h), s.Margin).Add(bounds.Min)
 	s.Proxy.Arrange(ctx, content, offset)
 }
 
@@ -85,8 +85,8 @@ func (s *Spacing) DesiredSize(ctx Context) geom.PointF32 {
 	var size = s.Proxy.DesiredSize(ctx)
 	var w, h = s.Width.Zero(size.X), s.Height.Zero(size.Y)
 	return geom.PtF32(
-		s.Margin.Left.Value()+w.Value()+s.Margin.Right.Value(),
-		s.Margin.Top.Value()+h.Value()+s.Margin.Bottom.Value())
+		s.Margin.Left.Value()+w+s.Margin.Right.Value(),
+		s.Margin.Top.Value()+h+s.Margin.Bottom.Value())
 }
 
 func (s *Spacing) SetSize(w, h float32) {
@@ -95,7 +95,7 @@ func (s *Spacing) SetSize(w, h float32) {
 }
 
 // FixedSize wraps the Control c to fill exactly the space specified.
-func FixedSize(c Control, w, h float32) Control {
+func FixedSize(c Control, w, h float32) *Spacing {
 	return BuildSpacing(c, func(s *Spacing) {
 		s.Width = Fixed(w)
 		s.Height = Fixed(h)
@@ -103,7 +103,7 @@ func FixedSize(c Control, w, h float32) Control {
 }
 
 // FixedHeight wraps the Control c to fill exactly the height specified. Width is taken from Control c.
-func FixedHeight(c Control, h float32) Control {
+func FixedHeight(c Control, h float32) *Spacing {
 	return BuildSpacing(c, func(s *Spacing) {
 		s.Height = Fixed(h)
 	})
@@ -148,10 +148,10 @@ func stretch(c Control, w, h bool) *Spacing {
 }
 
 // Stretch wraps the Control c to stretch in both directions.
-func Stretch(c Control) Control { return stretch(c, true, true) }
+func Stretch(c Control) *Spacing { return stretch(c, true, true) }
 
 // StretchHeight wraps the Control c to stretch vertically. Width is taken from Control c.
-func StretchHeight(c Control) Control { return stretch(c, false, true) }
+func StretchHeight(c Control) *Spacing { return stretch(c, false, true) }
 
 // StretchWidth wraps the Control c to stretch horizontally. Height is taken from Control c.
-func StretchWidth(c Control) Control { return stretch(c, true, false) }
+func StretchWidth(c Control) *Spacing { return stretch(c, true, false) }