diff --git a/doc/config.html b/doc/config.html
index 780c2278..f7acc2ef 100755
--- a/doc/config.html
+++ b/doc/config.html
@@ -236,7 +236,9 @@ The logbook tabs would then look like this:<p>
 <img src="tabs.gif"><p>
 
 Where the selected group or logbook becomes blue. The lower groups/logbooks change according
-to the selected upper group.<p>
+to the selected upper group. Please note that a logbook can be contained in more than one
+group, but then it should not be the first logbook in those groups. The colors of the tabs
+and the title bar can be specified in the theme file.<p>
 
 <hr>
 <div class=title>&nbsp; Individual logbook options &nbsp;</div>