rwm: clarify behavior of multiple set_borders

 protocol/river-window-management-v1.xml | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/protocol/river-window-management-v1.xml b/protocol/river-window-management-v1.xml
index cd5a516..9f443f5 100644
--- a/protocol/river-window-management-v1.xml
+++ b/protocol/river-window-management-v1.xml
@@ -406,6 +406,9 @@
         Setting the edges to none or the width to 0 disables the borders.
         Setting a negative width is a protocol error.
 
+        This request completely overrides all previous set_borders requests.
+        Only the most recent set_borders request has an effect.
+
         This request is double-buffered state and will not be applied until the
         next river_window_manager_v1.commit request.
       </description>