[Golang] No function list in the navigate window

tomcat:8.5.34
opengrok: 1.1-rc41

Universal Ctags 0.0.0(d0807887), Copyright (C) 2015 Universal Ctags Team
Universal Ctags is derived from Exuberant Ctags.
Exuberant Ctags 5.8, Copyright (C) 1996-2009 Darren Hiebert
  Optional compiled features: +wildcards, +regex, +iconv, +option-directory

I use opengrok, with default config to index golang source code, but there is no function list in the nagivate window,

I try to index with -o option:

./opengrok/bin/indexer.py \
    -a $OPENGROK/lib/opengrok.jar -- \
    -c /opt/ctags/bin/ctags \
    -o ctags.conf \
    -s $PWD/repo/src -d $PWD/repo/data -H -P -S -G \
    -W $PWD/configuration.xml \
    -U http://localhost:8080

and the ctags.conf is:

--langdef=golang
--langmap=golang:.go
--regex-golang=/func([ \t]+\([^)]+\))?[ \t]+([a-zA-Z0-9_]+)/\2/d,func/
--regex-golang=/var[ \t]+([a-zA-Z_][a-zA-Z0-9_]+)/\1/d,var/
--regex-golang=/type[ \t]+([a-zA-Z_][a-zA-Z0-9_]+)/\1/d,type/

but still doesn't work.

Any help? Thanks!