set_navigation_tab_main is a hook location. That is selected when you create a plugin. The code he posted is for the plugin. https://www.vbulletin.com/docs/html/plugin_system

ok the link helped a bit now i have
http://www.xboxplayers.co.uk/site/images/hookplugin.jpg

i guess as i dont know what array is ive got that wrong

You need to replace this:
(in_array($GLOBALS['forumid'], array(2,15)))

with a condition unique to your page.

Sorry to be dumb Lynne but i don't understand what condition i would even begin to look for i tried forum/forums thinking it goes with the php page somehow, the forum id is definitely 6 but again i don't understand array where do i begin?

i want to show one of my forums completely in new tab
but how can i set sub forums or sub threads on that forum highlight?

--------------- Added [DATE]1340307067[/DATE] at [TIME]1340307067[/TIME] ---------------

any idea?

You would need to put all the forumids into the condition.

its work fine on all forums i set
thank you
but when a thread on that forums opened, default tab selected again
what should we do with threads?

It works just fine on my test site for all the threads. Can you please post *exacly* what you have done?

all treads created in forum 148 has this problem

How do I set up the navigation manager so that when the current page is support page that the support menu STAYS in the navigation bar? What's happening is once I click the links in the menus or links I created via the navigation manager, it shows the default forum links in the navigation bar and I definitely DO NOT want that. Any clues?