Monika,
A quick answer is to go to acs-subiste parameters (i.e.
http://you-domain/shared/parameters )
Scroll down to Navigation Tabs and find the parameter "UserNavbarTabsList". You can add more items within it. The ones you would like to avoid you can add within "NoTabApplicationList"
A bit of context:
OpenACS website uses its own theme. Most of its code is available in the core already.
However, I don't remember myself browsing through these sources: the top navigation (i.e. blue header and logo) is not there yet.
You might want to start:
1. reading packages/openacs-default-theme/lib/plain-master.adp/tab-master.adp;
2. visiting acs-sbusite configurations. You can edit website there from there.
For example, mine is /packages/theme-zen/lib/lrn-master
3. visiting acs-subiste parameters http://you-domain/shared/parameters
You might want to create your own theme, based on openacs-default-theme. Then you add a mixture TCL (i.e. categories pkg) and javascript, bootstrap, and CSS... the creativity is limitless.
Plus, you might use Xowiki pkg for that. Creating a new theme for Xowiki could be trickier than the solution above. Gustaf could describe it better. https://openacs.org/xowiki/xowiki
I don't know if I had answered your question.
Best wishes,
I
