diff --git a/docs/labwc-config.5.scd b/docs/labwc-config.5.scd
index ac20dcb7..db01c469 100644
--- a/docs/labwc-config.5.scd
+++ b/docs/labwc-config.5.scd
@@ -122,9 +122,12 @@ this is for compatibility with Openbox.
 	The distance in pixels between views and output edges when using
 	movement actions, for example MoveToEdge. Default is 0.
 
-*<core><adaptiveSync>* [yes|no]
+*<core><adaptiveSync>* [yes|no|fullscreen]
 	Enable adaptive sync. Default is no.
 
+	*fullscreen* enables adaptive sync whenever a window is in fullscreen
+	mode.
+
 *<core><reuseOutputMode>* [yes|no]
 	Try to re-use the existing output mode (resolution / refresh rate).
 	This may prevent unnecessary screenblank delays when starting labwc