treeview: Add a diagram to CSS documentation

diff --git a/gtk/gtktreeview.c b/gtk/gtktreeview.c
index 282df7ea5a2ca6b889880fbfa096c9ba078817ca..854583539836e481e0e70278475a8cee01d3aef1 100644 (file)
--- a/gtk/gtktreeview.c
+++ b/gtk/gtktreeview.c
@@ -126,9 +126,20 @@
  *
  * # CSS nodes
  *
+ * |[<!-- language="plain" -->
+ * treeview.view
+ * ├── header
+ * │   ├── [column header]
+ * │   ├── [column header]
+   ┊   ┊
+ * │
+ * ╰── [rubberband]
+ * ]|
+ *
  * GtkTreeView has a main CSS node with name treeview and style class .view.
  * It has a subnode with name header, which is the parent for all the column
  * header widgets' CSS nodes.
+ * For rubberband selection, a subnode with name rubberband is used.
  */
 
 enum