[gtk/gtk-3-24] Overlay: Document overlay children aren't measured

[Daniel Boles <dboles src gnome org>]

commit 41195785628fbcdd2950203b086646a898b6009e
Author: Daniel Boles <dboles src gmail com>
Date:   Thu Jun 13 18:22:33 2019 +0100

    Overlay: Document overlay children aren't measured
    
    Some users expect that the Overlay will automatically request enough
    size for its overlay children as well as its main child. It doesn't,
    because it's just a GtkBin. Add a short paragraph pointing that out.
    
    Close https://gitlab.gnome.org/GNOME/gtk/issues/1939

 gtk/gtkoverlay.c | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/gtk/gtkoverlay.c b/gtk/gtkoverlay.c
index be0788dfc6..030fe614cd 100644
--- a/gtk/gtkoverlay.c
+++ b/gtk/gtkoverlay.c
@@ -46,6 +46,9 @@
  * More complicated placement of overlays is possible by connecting
  * to the #GtkOverlay::get-child-position signal.
  *
+ * An overlay’s minimum and natural sizes are those of its main child. The sizes
+ * of overlay children are not considered when measuring these preferred sizes.
+ *
  * # GtkOverlay as GtkBuildable
  *
  * The GtkOverlay implementation of the GtkBuildable interface