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

diff --git a/gtk/gtkoverlay.c b/gtk/gtkoverlay.c
index 7001aa59ba45579ca4f771a12c4a159cc0da70ca..f23982221e62a7b73c9640077a71fd5c9537e7bd 100644 (file)
--- a/gtk/gtkoverlay.c
+++ b/gtk/gtkoverlay.c
@@ -50,6 +50,9 @@
  * 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