[gtk+] scrolledwindow: Document overlay scrolling style classes

[Matthias Clasen <matthiasc src gnome org>]

commit cf7f23f4ddc191c2ce91192b0d8f07c625b25a08
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Nov 6 23:35:20 2015 -0500

    scrolledwindow: Document overlay scrolling style classes
    
    Document which style classes are used on scrollbars to
    implement overlay scrolling.

 gtk/gtkscrollbar.c      |    4 ++++
 gtk/gtkscrolledwindow.c |    3 ++-
 2 files changed, 6 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtkscrollbar.c b/gtk/gtkscrollbar.c
index 29e8e63..06ddc50 100644
--- a/gtk/gtkscrollbar.c
+++ b/gtk/gtkscrollbar.c
@@ -74,6 +74,10 @@
  * If steppers are enabled, they are represented by up to four additional
  * subnodes with name button. These get the style classes .up and .down to
  * indicate in which direction they are moving.
+ *
+ * Other style classes that may be added to scrollbars inside #GtkScrolledWindow
+ * include the positional classes (.left, .right, .top, .bottom) and style
+ * classes related to overlay scrolling (.overlay-indicator, .dragging, .hovering).
  */
 
 
diff --git a/gtk/gtkscrolledwindow.c b/gtk/gtkscrolledwindow.c
index ef55d40..da37c0d 100644
--- a/gtk/gtkscrolledwindow.c
+++ b/gtk/gtkscrolledwindow.c
@@ -116,7 +116,8 @@
  * on where the indication is drawn.
  *
  * GtkScrolledWindow also sets the positional style classes (.left,
- * .right, .top, .bottom) on the scrollbars.
+ * .right, .top, .bottom) and style classes related to overlay
+ * scrolling (.overlay-indicator, .dragging, .hovering) on its scrollbars.
  *
  * If both scrollbars are visible, the area where they meet is drawn
  * with a subnode named junction.