diff --git a/libs/ui/include/psemek/ui/impl/box_layout_base.hpp b/libs/ui/include/psemek/ui/impl/box_layout_base.hpp
index 9f0973cc..ef40d72e 100644
--- a/libs/ui/include/psemek/ui/impl/box_layout_base.hpp
+++ b/libs/ui/include/psemek/ui/impl/box_layout_base.hpp
@@ -37,7 +37,7 @@ namespace psemek::ui::impl
 		box_layout_base(react::value<float> margin);
 
 		void reshape(geom::box<float, 2> const & new_shape) override;
-		react::value<size_polygon> size_constraints() const override;
+		react::value<struct size_constraints> size_constraints() const override;
 
 		void set_children(std::vector<std::unique_ptr<component>> children) override;
 		std::vector<std::unique_ptr<component>> release_children() override;
@@ -47,8 +47,8 @@ namespace psemek::ui::impl
 	private:
 		react::value<float> margin_;
 		react::value<std::vector<react::value<box_layout::size_policy>>> size_policies_;
-		react::source<std::vector<react::value<size_polygon>>> children_size_constraints_;
-		react::value<size_polygon> size_constraints_;
+		react::source<std::vector<react::value<struct size_constraints>>> children_size_constraints_;
+		react::value<struct size_constraints> size_constraints_;
 	};
 
 	extern template struct box_layout_base<0>;
diff --git a/libs/ui/include/psemek/ui/impl/component.hpp b/libs/ui/include/psemek/ui/impl/component.hpp
index 55868c49..f8045f3e 100644
--- a/libs/ui/include/psemek/ui/impl/component.hpp
+++ b/libs/ui/include/psemek/ui/impl/component.hpp
@@ -1,6 +1,6 @@
 #pragma once
 
-#include <psemek/ui/impl/size_polygon.hpp>
+#include <psemek/ui/impl/size_constraints.hpp>
 #include <psemek/react/value.hpp>
 #include <psemek/geom/box.hpp>
 #include <psemek/geom/interval.hpp>
@@ -15,15 +15,12 @@ namespace psemek::ui::impl
 	{
 		static constexpr float infinity = std::numeric_limits<float>::infinity();
 
-		static size_polygon const & default_size_polygon();
-		static react::value<size_polygon> default_size_constraints();
-
 		virtual util::span<std::unique_ptr<component> const> children() const;
 
 		virtual geom::box<float, 2> const & shape() const;
 		virtual void reshape(geom::box<float, 2> const & new_shape);
 
-		virtual react::value<size_polygon> size_constraints() const;
+		virtual react::value<struct size_constraints> size_constraints() const;
 
 		virtual ~component() {}
 
diff --git a/libs/ui/include/psemek/ui/impl/single_container.hpp b/libs/ui/include/psemek/ui/impl/single_container.hpp
index 7e0c6b67..b049391a 100644
--- a/libs/ui/include/psemek/ui/impl/single_container.hpp
+++ b/libs/ui/include/psemek/ui/impl/single_container.hpp
@@ -4,8 +4,6 @@
 #include <psemek/ui/key.hpp>
 #include <psemek/util/signal.hpp>
 
-#include <any>
-
 namespace psemek::ui::impl
 {
 
diff --git a/libs/ui/include/psemek/ui/impl/single_container_base.hpp b/libs/ui/include/psemek/ui/impl/single_container_base.hpp
index 8f8b2f44..20b397eb 100644
--- a/libs/ui/include/psemek/ui/impl/single_container_base.hpp
+++ b/libs/ui/include/psemek/ui/impl/single_container_base.hpp
@@ -13,15 +13,15 @@ namespace psemek::ui::impl
 		single_container_base(react::value<geom::vector<float, 2>> margin);
 
 		void reshape(geom::box<float, 2> const & new_shape) override;
-		react::value<size_polygon> size_constraints() const override;
+		react::value<struct size_constraints> size_constraints() const override;
 
 		void set_child(std::unique_ptr<component> child) override;
 		std::unique_ptr<component> release_child() override;
 
 	private:
 		react::value<geom::vector<float, 2>> margin_;
-		react::source<react::value<size_polygon>> child_size_constraints_;
-		react::value<size_polygon> size_constraints_;
+		react::source<react::value<struct size_constraints>> child_size_constraints_;
+		react::value<struct size_constraints> size_constraints_;
 	};
 
 }
diff --git a/libs/ui/include/psemek/ui/impl/size_constraints.hpp b/libs/ui/include/psemek/ui/impl/size_constraints.hpp
new file mode 100644
index 00000000..c6d3d21d
--- /dev/null
+++ b/libs/ui/include/psemek/ui/impl/size_constraints.hpp
@@ -0,0 +1,28 @@
+#pragma once
+
+#include <psemek/geom/box.hpp>
+
+namespace psemek::ui::impl
+{
+
+	struct size_constraints
+	{
+		geom::box<float, 2> box;
+
+		static size_constraints max();
+	};
+
+	size_constraints shift(size_constraints const & constraints, geom::vector<float, 2> const & delta);
+	size_constraints scale(size_constraints const & constraints, float factor, int dimension);
+
+	float min(size_constraints const & constraints, int dimension);
+
+	size_constraints intersect(size_constraints const & constraints1, size_constraints const & constraints2);
+
+	geom::interval<float> range(size_constraints const & constraints, int dimension);
+
+	size_constraints cut(size_constraints const & constraints, int dimension, geom::interval<float> const & range);
+
+	size_constraints sum_along(size_constraints const & constraints1, size_constraints const & constraints2, int dimension);
+
+}
diff --git a/libs/ui/include/psemek/ui/impl/size_polygon.hpp b/libs/ui/include/psemek/ui/impl/size_polygon.hpp
deleted file mode 100644
index bbd48976..00000000
--- a/libs/ui/include/psemek/ui/impl/size_polygon.hpp
+++ /dev/null
@@ -1,15 +0,0 @@
-#pragma once
-
-#include <psemek/geom/point.hpp>
-
-#include <vector>
-
-namespace psemek::ui::impl
-{
-
-	constexpr float max_size = 16384.f;
-
-	// Convex, in CCW order
-	using size_polygon = std::vector<geom::point<float, 2>>;
-
-}
diff --git a/libs/ui/include/psemek/ui/impl/size_polygon_utils.hpp b/libs/ui/include/psemek/ui/impl/size_polygon_utils.hpp
deleted file mode 100644
index e9cdb60f..00000000
--- a/libs/ui/include/psemek/ui/impl/size_polygon_utils.hpp
+++ /dev/null
@@ -1,19 +0,0 @@
-#pragma once
-
-#include <psemek/ui/impl/size_polygon.hpp>
-#include <psemek/geom/interval.hpp>
-
-namespace psemek::ui::impl
-{
-
-	size_polygon shift(size_polygon polygon, geom::vector<float, 2> const & delta);
-
-	size_polygon min(size_polygon const & polygon, int dimension);
-
-	size_polygon intersect(size_polygon const & polygon1, size_polygon const & polygon2);
-
-	geom::interval<float> range(size_polygon const & polygon, int dimension);
-	size_polygon cut(size_polygon const & polygon, int dimension, geom::interval<float> const & range);
-	size_polygon sum_along(size_polygon const & polygon1, size_polygon const & polygon2, int dimension);
-
-}
diff --git a/libs/ui/include/psemek/ui/impl/stack_layout_base.hpp b/libs/ui/include/psemek/ui/impl/stack_layout_base.hpp
index e5e0ca43..fc994816 100644
--- a/libs/ui/include/psemek/ui/impl/stack_layout_base.hpp
+++ b/libs/ui/include/psemek/ui/impl/stack_layout_base.hpp
@@ -14,7 +14,7 @@ namespace psemek::ui::impl
 		stack_layout_base();
 
 		void reshape(geom::box<float, 2> const & new_shape) override;
-		react::value<size_polygon> size_constraints() const override;
+		react::value<struct size_constraints> size_constraints() const override;
 
 		void set_children(std::vector<std::unique_ptr<component>> children) override;
 		std::vector<std::unique_ptr<component>> release_children() override;
@@ -23,8 +23,8 @@ namespace psemek::ui::impl
 		{}
 
 	private:
-		react::source<std::vector<react::value<size_polygon>>> children_size_constraints_;
-		react::value<size_polygon> size_constraints_;
+		react::source<std::vector<react::value<struct size_constraints>>> children_size_constraints_;
+		react::value<struct size_constraints> size_constraints_;
 	};
 
 }
diff --git a/libs/ui/source/impl/box_layout_base.cpp b/libs/ui/source/impl/box_layout_base.cpp
index 23adaa36..f3208200 100644
--- a/libs/ui/source/impl/box_layout_base.cpp
+++ b/libs/ui/source/impl/box_layout_base.cpp
@@ -1,5 +1,4 @@
 #include <psemek/ui/impl/box_layout_base.hpp>
-#include <psemek/ui/impl/size_polygon_utils.hpp>
 #include <psemek/react/map.hpp>
 #include <psemek/react/join.hpp>
 
@@ -12,25 +11,22 @@ namespace psemek::ui::impl
 		static constexpr box_layout::size_policy default_policy = box_layout::weight{};
 
 		template <int Dimension>
-		size_polygon compute_size_constraints(std::vector<box_layout::size_policy> const & size_policies,
-			std::vector<size_polygon const *> const & children_size_constraints, float margin)
+		size_constraints compute_size_constraints(std::vector<box_layout::size_policy> const & size_policies,
+			std::vector<size_constraints> const & children_size_constraints, float margin)
 		{
-			size_polygon minimized{{0.f, 0.f}, {0.f, max_size}};
-			size_polygon weight_unit = minimized;
+			size_constraints minimized = size_constraints::max();
+			size_constraints weight_unit = minimized;
 			float weight_sum = 0.f;
 
 			for (std::size_t i = 0; i < size_policies.size(); ++i)
 			{
 				if (std::get_if<box_layout::minimized>(&size_policies[i]))
 				{
-					minimized = sum_along(minimized, *children_size_constraints[i], Dimension);
+					minimized = sum_along(minimized, children_size_constraints[i], Dimension);
 				}
 				else if (auto weight = std::get_if<box_layout::weight>(&size_policies[i]))
 				{
-					size_polygon child = *children_size_constraints[i];
-					for (auto & p : child)
-						p[Dimension] /= weight->value;
-					weight_unit = sum_along(weight_unit, child, Dimension);
+					weight_unit = intersect(weight_unit, scale(children_size_constraints[i], 1.f / weight->value, Dimension));
 					weight_sum += weight->value;
 				}
 			}
@@ -38,17 +34,15 @@ namespace psemek::ui::impl
 			auto result = std::move(minimized);
 
 			if (weight_sum > 0.f)
+				result = sum_along(result, scale(weight_unit, weight_sum, Dimension), Dimension);
+
+			if (size_policies.size() > 0)
 			{
-				for (auto & p : weight_unit)
-					p[Dimension] *= weight_sum;
-				result = sum_along(result, weight_unit, Dimension);
+				geom::vector shift_delta{0.f, 0.f};
+				shift_delta[Dimension] = margin * (size_policies.size() - 1);
+				result = shift(std::move(result), shift_delta);
 			}
 
-			geom::vector shift_delta{0.f, 0.f};
-			shift_delta[Dimension] = margin;
-
-			result = shift(std::move(result), shift_delta);
-
 			return result;
 		}
 
@@ -68,7 +62,7 @@ namespace psemek::ui::impl
 
 				if (std::get_if<box_layout::minimized>(&policy))
 				{
-					result[i] = min(*children[i]->size_constraints(), Dimension).front()[Dimension];
+					result[i] = min(*children[i]->size_constraints(), Dimension);
 					total_size -= result[i];
 				}
 				else if (auto weight = std::get_if<box_layout::weight>(&policy))
@@ -98,12 +92,16 @@ namespace psemek::ui::impl
 		: margin_(margin)
 		, size_policies_({})
 		, children_size_constraints_()
-		, size_constraints_(react::map([](auto const & size_policies, auto const & children_size_constraints, auto const & margin){
-			return compute_size_constraints<Dimension>(size_policies, children_size_constraints, margin);
-		},
-			react::join(react::map(react::unpack_with_default(default_policy), size_policies_)),
-			react::join(react::map(react::unpack_with_transform([](react::value<size_polygon> const & arg){ return &(*arg); }), children_size_constraints_)),
-			margin_))
+		, size_constraints_(
+			react::map(
+				[](auto const & size_policies, auto const & children_size_constraints, auto const & margin){
+					return compute_size_constraints<Dimension>(size_policies, children_size_constraints, margin);
+				},
+				react::join(react::map(react::unpack_with_default(default_policy), size_policies_)),
+				react::join(react::map(react::unpack, children_size_constraints_)),
+				margin_
+			)
+		)
 	{}
 
 	template <int Dimension>
@@ -134,7 +132,7 @@ namespace psemek::ui::impl
 	}
 
 	template <int Dimension>
-	react::value<size_polygon> box_layout_base<Dimension>::size_constraints() const
+	react::value<size_constraints> box_layout_base<Dimension>::size_constraints() const
 	{
 		return size_constraints_;
 	}
@@ -144,13 +142,13 @@ namespace psemek::ui::impl
 	{
 		container::set_children(std::move(children));
 
-		std::vector<react::value<size_polygon>> children_size_constraints;
+		std::vector<react::value<struct size_constraints>> children_size_constraints;
 		for (auto const & child : this->children())
 		{
 			if (child)
 				children_size_constraints.push_back(child->size_constraints());
 			else
-				children_size_constraints.push_back(default_size_constraints());
+				children_size_constraints.push_back(size_constraints::max());
 		}
 		children_size_constraints_.set(std::move(children_size_constraints));
 	}
diff --git a/libs/ui/source/impl/component.cpp b/libs/ui/source/impl/component.cpp
index 42056643..4b468176 100644
--- a/libs/ui/source/impl/component.cpp
+++ b/libs/ui/source/impl/component.cpp
@@ -3,24 +3,6 @@
 namespace psemek::ui::impl
 {
 
-	size_polygon const & component::default_size_polygon()
-	{
-		static size_polygon const result{{
-			{max_size, 0.f},
-			{0.f, 0.f},
-			{0.f, max_size},
-			{max_size, max_size}
-		}};
-
-		return result;
-	}
-
-	react::value<size_polygon> component::default_size_constraints()
-	{
-		static react::value<size_polygon> const result{default_size_polygon()};
-		return result;
-	}
-
 	util::span<std::unique_ptr<component> const> component::children() const
 	{
 		return {};
@@ -36,9 +18,10 @@ namespace psemek::ui::impl
 		shape_ = new_shape;
 	}
 
-	react::value<size_polygon> component::size_constraints() const
+	react::value<size_constraints> component::size_constraints() const
 	{
-		return default_size_constraints();
+		static react::value<struct size_constraints> const result{size_constraints::max()};
+		return result;
 	}
 
 }
diff --git a/libs/ui/source/impl/single_container_base.cpp b/libs/ui/source/impl/single_container_base.cpp
index 7b37379b..2ce179f0 100644
--- a/libs/ui/source/impl/single_container_base.cpp
+++ b/libs/ui/source/impl/single_container_base.cpp
@@ -1,5 +1,4 @@
 #include <psemek/ui/impl/single_container_base.hpp>
-#include <psemek/ui/impl/size_polygon_utils.hpp>
 #include <psemek/react/map.hpp>
 #include <psemek/react/join.hpp>
 
@@ -8,8 +7,8 @@ namespace psemek::ui::impl
 
 	single_container_base::single_container_base(react::value<geom::vector<float, 2>> margin)
 		: margin_(margin)
-		, child_size_constraints_(default_size_constraints())
-		, size_constraints_(react::map([](size_polygon const & child_constraints, geom::vector<float, 2> const & margin){
+		, child_size_constraints_(size_constraints::max())
+		, size_constraints_(react::map([](struct size_constraints const & child_constraints, geom::vector<float, 2> const & margin){
 				return shift(child_constraints, margin);
 			}, react::join(child_size_constraints_), margin))
 	{}
@@ -22,7 +21,7 @@ namespace psemek::ui::impl
 			child()->reshape(geom::shrink(new_shape, *margin_));
 	}
 
-	react::value<size_polygon> single_container_base::size_constraints() const
+	react::value<size_constraints> single_container_base::size_constraints() const
 	{
 		return size_constraints_;
 	}
@@ -30,13 +29,13 @@ namespace psemek::ui::impl
 	void single_container_base::set_child(std::unique_ptr<component> child)
 	{
 		single_container::set_child(std::move(child));
-		child_size_constraints_.set(this->child() ? this->child()->size_constraints() : default_size_constraints());
+		child_size_constraints_.set(this->child() ? this->child()->size_constraints() : size_constraints::max());
 	}
 
 	std::unique_ptr<component> single_container_base::release_child()
 	{
 		auto child = single_container::release_child();
-		child_size_constraints_.set(default_size_constraints());
+		child_size_constraints_.set(size_constraints::max());
 		return child;
 	}
 
diff --git a/libs/ui/source/impl/size_constraints.cpp b/libs/ui/source/impl/size_constraints.cpp
new file mode 100644
index 00000000..5ac0796f
--- /dev/null
+++ b/libs/ui/source/impl/size_constraints.cpp
@@ -0,0 +1,63 @@
+#include <psemek/ui/impl/size_constraints.hpp>
+
+#include <limits>
+
+namespace psemek::ui::impl
+{
+
+	size_constraints size_constraints::max()
+	{
+		static constexpr float infinity = std::numeric_limits<float>::infinity();
+
+		return
+		{{{
+			{0.f, infinity},
+			{0.f, infinity},
+		}}};
+	}
+
+	size_constraints shift(size_constraints const & constraints, geom::vector<float, 2> const & delta)
+	{
+		return {constraints.box + delta};
+	}
+
+	size_constraints scale(size_constraints const & constraints, float factor, int dimension)
+	{
+		auto result = constraints;
+		result.box[dimension].min *= factor;
+		result.box[dimension].max *= factor;
+		return result;
+	}
+
+	float min(size_constraints const & constraints, int dimension)
+	{
+		return constraints.box[dimension].min;
+	}
+
+	size_constraints intersect(size_constraints const & constraints1, size_constraints const & constraints2)
+	{
+		return {constraints1.box & constraints2.box};
+	}
+
+	geom::interval<float> range(size_constraints const & constraints, int dimension)
+	{
+		return constraints.box[dimension];
+	}
+
+	size_constraints cut(size_constraints const & constraints, int dimension, geom::interval<float> const & range)
+	{
+		size_constraints result = constraints;
+		result.box[dimension] &= range;
+		return result;
+	}
+
+	size_constraints sum_along(size_constraints const & constraints1, size_constraints const & constraints2, int dimension)
+	{
+		size_constraints result;
+		result.box[dimension].min = constraints1.box[dimension].min + constraints2.box[dimension].min;
+		result.box[dimension].max = constraints1.box[dimension].max + constraints2.box[dimension].max;
+		result.box[dimension ^ 1] = constraints1.box[dimension ^ 1] & constraints2.box[dimension ^ 1];
+		return result;
+	}
+
+}
diff --git a/libs/ui/source/impl/size_polygon_utils.cpp b/libs/ui/source/impl/size_polygon_utils.cpp
deleted file mode 100644
index 37d80af0..00000000
--- a/libs/ui/source/impl/size_polygon_utils.cpp
+++ /dev/null
@@ -1,135 +0,0 @@
-#include <psemek/ui/impl/size_polygon_utils.hpp>
-#include <psemek/geom/math.hpp>
-#include <psemek/util/not_implemented.hpp>
-#include <psemek/util/cyclic_iterator.hpp>
-
-namespace psemek::ui::impl
-{
-
-	size_polygon shift(size_polygon polygon, geom::vector<float, 2> const & delta)
-	{
-		for (auto & p : polygon)
-			p += delta;
-		return polygon;
-	}
-
-	size_polygon min(size_polygon const & polygon, int dimension)
-	{
-		if (polygon.empty())
-			return {};
-
-		size_polygon result;
-
-		auto cit = util::make_cyclic_iterator(polygon);
-		std::size_t iterations = 0;
-
-		for (auto next = std::next(cit); (*next)[dimension] <= (*cit)[dimension] && iterations < polygon.size(); cit = next++, ++iterations);
-
-		if (iterations == polygon.size())
-			return polygon;
-
-		for (auto prev = std::prev(cit); (*prev)[dimension] <= (*cit)[dimension]; cit = prev--);
-
-		for (auto cjt = cit; (*cjt)[dimension] == (*cit)[dimension]; ++cjt)
-			result.push_back(*cjt);
-
-		return result;
-	}
-
-	size_polygon intersect(size_polygon const & polygon1, size_polygon const & polygon2)
-	{
-		// TODO: https://www.cs.jhu.edu/~misha/Spring16/ORourke82.pdf
-		(void)polygon1;
-		(void)polygon2;
-		util::not_implemented();
-	}
-
-	geom::interval<float> range(size_polygon const & polygon, int dimension)
-	{
-		geom::interval<float> result;
-		for (auto const & p : polygon)
-			result |= p[dimension];
-		return result;
-	}
-
-	size_polygon cut(size_polygon const & polygon, int dimension, geom::interval<float> const & range)
-	{
-		size_polygon result;
-		std::size_t iterations = 0;
-		for (auto it = util::make_cyclic_iterator(polygon), next_it = std::next(it); iterations != polygon.size(); (it = next_it++), ++iterations)
-		{
-			auto const & curr = *it;
-			auto const & next = *next_it;
-
-			auto intersection = [&](float value)
-			{
-				// curr + (next - curr) * t = value
-				float t = (value - curr[dimension]) / (next[dimension] - curr[dimension]);
-				geom::point<float, 2> p;
-				p[dimension] = value;
-				p[dimension ^ 1] = geom::lerp(curr[dimension ^ 1], next[dimension ^ 1], t);
-				return p;
-			};
-
-			auto classify = [&](float value)
-			{
-				if (value < range.min)
-					return -2;
-				else if (value == range.min)
-					return -1;
-				else if (value < range.max)
-					return 0;
-				else if (value == range.max)
-					return 1;
-				else // (value > range.max)
-					return 2;
-			};
-
-			int const curr_class = classify(curr[dimension]);
-			int const next_class = classify(next[dimension]);
-
-			if (curr_class >= -1 && curr_class <= 1)
-				result.push_back(curr);
-
-			bool const min = (curr_class == -2 && next_class >= 0) || (curr_class >= 0 && next_class == -2);
-			bool const max = (curr_class ==  2 && next_class <= 0) || (curr_class <= 0 && next_class ==  2);
-
-
-			if (range.min == range.max)
-			{
-				if (min) result.push_back(intersection(range.min));
-			}
-			else
-			{
-				if (min) result.push_back(intersection(range.min));
-				if (max) result.push_back(intersection(range.max));
-
-				if (min && max && curr_class == 2)
-					std::swap(result.back(), result[result.size() - 2]);
-			}
-		}
-
-		return result;
-	}
-
-	size_polygon sum_along(size_polygon const & polygon1, size_polygon const & polygon2, int dimension)
-	{
-		if (polygon1.empty() || polygon2.empty())
-			return size_polygon{};
-
-		int const other_dimension = dimension ^ 1;
-
-		auto range1 = range(polygon1, other_dimension);
-		auto range2 = range(polygon2, other_dimension);
-
-		auto common_range = range1 & range2;
-		if (common_range.empty())
-			return size_polygon{};
-
-		auto cut1 = cut(polygon1, other_dimension, common_range);
-		auto cut2 = cut(polygon2, other_dimension, common_range);
-
-		util::not_implemented();
-	}
-
-}
diff --git a/libs/ui/source/impl/stack_layout_base.cpp b/libs/ui/source/impl/stack_layout_base.cpp
index 95a7f648..03c25ab5 100644
--- a/libs/ui/source/impl/stack_layout_base.cpp
+++ b/libs/ui/source/impl/stack_layout_base.cpp
@@ -1,5 +1,4 @@
 #include <psemek/ui/impl/stack_layout_base.hpp>
-#include <psemek/ui/impl/size_polygon_utils.hpp>
 #include <psemek/react/join.hpp>
 #include <psemek/react/map.hpp>
 
@@ -9,14 +8,11 @@ namespace psemek::ui::impl
 	namespace
 	{
 
-		size_polygon compute_size_constraints(std::vector<size_polygon const *> const & children_size_constraints)
+		size_constraints compute_size_constraints(std::vector<size_constraints> const & children_size_constraints)
 		{
-			if (children_size_constraints.empty())
-				return component::default_size_polygon();
-
-			auto result = *children_size_constraints.front();
-			for (std::size_t i = 1; i < children_size_constraints.size(); ++i)
-				result = intersect(result, *children_size_constraints[i]);
+			size_constraints result = size_constraints::max();
+			for (auto const & constraints : children_size_constraints)
+				result = intersect(result, constraints);
 			return result;
 		}
 
@@ -25,7 +21,7 @@ namespace psemek::ui::impl
 	stack_layout_base::stack_layout_base()
 		: size_constraints_(react::map([](auto const & children_size_constraints){
 			return compute_size_constraints(children_size_constraints);
-		}, react::join(react::map(react::unpack_with_transform([](react::value<size_polygon> const & arg){ return &(*arg); }), children_size_constraints_))))
+		}, react::join(react::map(react::unpack, children_size_constraints_))))
 	{}
 
 	void stack_layout_base::reshape(geom::box<float, 2> const & new_shape)
@@ -35,7 +31,7 @@ namespace psemek::ui::impl
 				child->reshape(new_shape);
 	}
 
-	react::value<size_polygon> stack_layout_base::size_constraints() const
+	react::value<size_constraints> stack_layout_base::size_constraints() const
 	{
 		return size_constraints_;
 	}
@@ -43,13 +39,13 @@ namespace psemek::ui::impl
 	void stack_layout_base::set_children(std::vector<std::unique_ptr<component>> children)
 	{
 		container::set_children(std::move(children));
-		std::vector<react::value<size_polygon>> children_size_constraints;
+		std::vector<react::value<struct size_constraints>> children_size_constraints;
 		for (auto const & child : this->children())
 		{
 			if (child)
 				children_size_constraints.push_back(child->size_constraints());
 			else
-				children_size_constraints.push_back(default_size_constraints());
+				children_size_constraints.push_back(size_constraints::max());
 		}
 		children_size_constraints_.set(std::move(children_size_constraints));
 	}