[PATCH 21/21] docs: Add details about grabs

[matthias.clasen at gmail.com]

From: Matthias Clasen <mclasen at redhat.com>

Mention implicit grabs, (lack of) explicit grabs, and popup
windows.
---
 doc/Wayland/en_US/Protocol.xml | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/doc/Wayland/en_US/Protocol.xml b/doc/Wayland/en_US/Protocol.xml
index a645409..b94e9ca 100644
--- a/doc/Wayland/en_US/Protocol.xml
+++ b/doc/Wayland/en_US/Protocol.xml
@@ -233,6 +233,14 @@
       in surface local coordinates.
     </para>
     <para>
+      The compositor maintains an implicit grab when a button is
+      pressed, to ensure that the corresponding button release
+      event gets delivered to the same surface. But there is way
+      for clients to take an explicit grab. Instead, surfaces can
+      be mapped as 'popup', which combines transient window semantics
+      with a pointer grab.
+    </para>
+    <para>
       See <xref linkend="protocol-spec-interface-wl_seat"/> for the
       protocol description.
     </para>
-- 
1.8.1.4