[gtk/ebassi/for-master] docs: Add a note on the "presentation" role

[Emmanuele Bassi <ebassi src gnome org>]

commit 041415e9b4f99b52cbc616ae465a17dc5d067b2e
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Thu Nov 5 14:50:40 2020 +0000

    docs: Add a note on the "presentation" role

 docs/reference/gtk/section-accessibility.md | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
---
diff --git a/docs/reference/gtk/section-accessibility.md b/docs/reference/gtk/section-accessibility.md
index efafadd512..b86aac419b 100644
--- a/docs/reference/gtk/section-accessibility.md
+++ b/docs/reference/gtk/section-accessibility.md
@@ -292,6 +292,20 @@ The power of hiding and enhancing can be a double-edged sword, as it can
 lead to inadvertently overriding the accessible semantics of existing
 widgets.
 
+## Hiding UI elements from the accessible tree
+
+The accessibility API is mainly used to express semantics useful for
+assistive technologies, but it can also be used to hide elements. The
+canonical way to do so is to use the %GTK_ACCESSIBLE_ROLE_PRESENTATION,
+which declares that a UI element is purely meant for presentation purposes,
+and as such it has no meaningful impact on the accessibility of the
+interface.
+
+A "presentation" role should not be confused with the
+%GTK_ACCESSIBLE_STATE_HIDDEN state; the "hidden" state is transient, and is
+typically controlled by showing and hiding a widget using the #GtkWidget
+API.
+
 ## Design patterns and custom widgets
 
 When creating custom widgets, following established patterns can help