Having trouble getting your split menu working on chosen pages in J 1.5? Here is how we worked around this...

The problem:

We have the main menu (top / parent level) on "all" pages.

We wanted the second level menu to appear on some pages that were not directly part of the menu.

So for example we have a page called "about Joomla!"  - there is no main menu item or sub-item pointing to this article.

We have implemented a hidden menu system & it contains a menu item pointing to the "about Joomla!". However, when we selected this item to display the split module - nothing happened.

Our solution:

We created a menu item linking to "about Joomla!" on the menu that we were splitting - in our case the main menu - and then selected that menu item when choosing to display the second level split menu. The rest is history.

Additional comment

This is quite interesting to us as we use the hidden menu items faultlessly to display other modules - but it seems this is not the case for the mainmenu_mod. Despite extensive googling - we didn't find any information on this - so we'd love to hear your comments if you know why this is so or have had a simliar experience.