UI elements should explicitly reset parent for their children

libs/ui/include/psemek/ui/button.hpp

@@ -30,6 +30,8 @@ namespace psemek::ui
 			callback_ = std::move(callback);
 		}
 
+		~button() override;
+
 	protected:
 		enum class state_t
 		{

libs/ui/include/psemek/ui/element.hpp

@@ -56,6 +56,9 @@ namespace psemek::ui
 		virtual void post(std::function<void()> f);
 		virtual void post_reshape();
 
+	protected:
+		virtual void release_children();
+
 	private:
 		element * parent_ = nullptr;
 		async::event_loop * loop_ = nullptr;

libs/ui/include/psemek/ui/frame.hpp

@@ -19,6 +19,8 @@ namespace psemek::ui
 		virtual std::optional<geom::vector<float, 2>> min_size() const { return min_size_; }
 		virtual std::optional<geom::vector<float, 2>> max_size() const { return max_size_; }
 
+		~frame() override;
+
 	private:
 		std::optional<geom::vector<float, 2>> min_size_;
 		std::optional<geom::vector<float, 2>> max_size_;

libs/ui/include/psemek/ui/grid_layout.hpp

@@ -42,6 +42,8 @@ namespace psemek::ui
 
 		void draw(painter &) const override {}
 
+		~grid_layout() override;
+
 	private:
 		util::array<std::shared_ptr<element>, 2> children_;
 		std::vector<element *> children_range_;

libs/ui/include/psemek/ui/screen.hpp

@@ -44,6 +44,8 @@ namespace psemek::ui
 
 		void draw(painter &) const override {}
 
+		~screen() override;
+
 	private:
 		container_impl container_;
 		box_shape shape_;

libs/ui/source/button.cpp

@@ -64,6 +64,11 @@ namespace psemek::ui
 		return false;
 	}
 
+	button::~button()
+	{
+		release_children();
+	}
+
 	void button::on_state_changed(state_t old)
 	{
 		auto s = merged_style();

libs/ui/source/element.cpp

@@ -95,4 +95,10 @@ namespace psemek::ui
 		});
 	}
 
+	void element::release_children()
+	{
+		for (auto c : children())
+			if (c) c->set_parent(nullptr);
+	}
+
 }

libs/ui/source/frame.cpp

@@ -34,4 +34,9 @@ namespace psemek::ui
 		post_reshape();
 	}
 
+	frame::~frame()
+	{
+		release_children();
+	}
+
 }

libs/ui/source/grid_layout.cpp

@@ -281,4 +281,9 @@ namespace psemek::ui
 		}
 	}
 
+	grid_layout::~grid_layout()
+	{
+		release_children();
+	}
+
 }

libs/ui/source/screen.cpp

@@ -113,4 +113,9 @@ namespace psemek::ui
 		return result;
 	}
 
+	screen::~screen()
+	{
+		release_children();
+	}
+
 }