Make ui::selector release children on destroy

libs/ui/include/psemek/ui/selector.hpp

@@ -11,6 +11,7 @@ namespace psemek::ui
 		: element
 	{
 		selector();
+		~selector() override;
 
 		children_range children() const override { return container_.children(); }
 

libs/ui/source/selector.cpp

@@ -14,6 +14,11 @@ namespace psemek::ui
 		: container_(this)
 	{}
 
+	selector::~selector()
+	{
+		release_children();
+	}
+
 	void selector::reshape(geom::box<float, 2> const & box)
 	{
 		shape_.box = box;