diff --git a/docs/labs.md b/docs/labs.md
index 6aa62d9ec4..d43c0b8e0e 100644
--- a/docs/labs.md
+++ b/docs/labs.md
@@ -172,3 +172,12 @@ the sender is using unknown/unrecognised event types.
 
 Sending events with extensible events structure is always enabled - this should not affect any downstream
 client.
+
+## Right panel stays open (`feature_right_panel_default_open`)
+
+This is an experimental default open right panel mode as a quick fix for those
+who prefer to have the right panel open consistently across rooms.
+
+If no right panel state is known for the room or it was closed on the last room
+visit, it will default to the room member list. Otherwise, the saved card last
+used in that room is shown.