+ /**
+ * Computes the vertical extents of the contents of this row item owner.
+ * @return A pair containing the minimum and maximum y-values.
+ */
+ std::pair<int, int> v_extents() const;
+
+ virtual void restack_items();
+
+public:
+ virtual void appearance_changed(bool label, bool content) = 0;
+
+ virtual void extents_changed(bool horz, bool vert) = 0;