document effect of contentless dependencies on sidebar efficiency

diff --git a/doc/plugins/sidebar.mdwn b/doc/plugins/sidebar.mdwn
index 36982eff386a31e91eaa3fade012795bb9fd61c1..4e356d65a8984885a256788f82f1f2173ffeaa67 100644 (file)
--- a/doc/plugins/sidebar.mdwn
+++ b/doc/plugins/sidebar.mdwn
@@ -16,6 +16,10 @@ will turn off the sidebar altogether.
 
 Warning: Any change to the sidebar will cause a rebuild of the whole wiki,
 since every page includes a copy that has to be updated. This can
-especially be a problem if the sidebar includes [[inline]] or [[map]]
-directives, since any changes to pages inlined or mapped onto the sidebar
+especially be a problem if the sidebar includes an [[ikiwiki/directive/inline]]
+directive, since any changes to pages inlined into the sidebar
 will change the sidebar and cause a full wiki rebuild.
+
+Instead, if you include a [[ikiwiki/directive/map]] directive on the sidebar,
+and it does not use the `show` parameter, only adding or removing pages
+included in the map will cause a full rebuild. Modifying pages will not.