diff --git a/docs/manual/manual.mk b/docs/manual/manual.mk
index aeafd10d7a..09265665a2 100644
--- a/docs/manual/manual.mk
+++ b/docs/manual/manual.mk
@@ -72,8 +72,8 @@ endef
 # The variable <DOCUMENT_NAME>_SOURCES defines the dependencies.
 ################################################################################
 define GENDOC
-$(call GENDOC_INNER,$(1),xhtml,html,html,HTML,--xsltproc-opts "--stringparam toc.section.depth 4")
-$(call GENDOC_INNER,$(1),chunked,split-html,chunked,split HTML,--xsltproc-opts "--stringparam toc.section.depth 4")
+$(call GENDOC_INNER,$(1),xhtml,html,html,HTML,--xsltproc-opts "--stringparam toc.section.depth 2")
+$(call GENDOC_INNER,$(1),chunked,split-html,chunked,split HTML,--xsltproc-opts "--stringparam toc.section.depth 2")
 $(call GENDOC_INNER,$(1),pdf,pdf,pdf,PDF,--dblatex-opts "-P latex.output.revhistory=0")
 $(call GENDOC_INNER,$(1),text,text,text,text)
 $(call GENDOC_INNER,$(1),epub,epub,epub,ePUB)