+ /**
+ * The extended area that the margin widget would like to be sized to.
+ * @remarks This area is the area specified by sizeHint, extended by
+ * the area to overlap the viewport.
+ */
+ virtual QSize extended_size_hint() const = 0;
+
+protected:
+ /**
+ * Gets the items in the margin widget.
+ */
+ virtual std::vector< std::shared_ptr<pv::view::ViewItem> > items() = 0;
+
+ /**
+ * Shows the popup of a the specified @c ViewItem .
+ * @param item The item to show the popup for.
+ */
+ void show_popup(const std::shared_ptr<ViewItem> &item);
+
+private:
+ void leaveEvent(QEvent *event);
+