I, too, am having troubles of this sort.
http://preview.tinyurl.com/3dexba <== is what I’ve got.
The home page is static and the posts page is named Posts and its slug is posts. And I would like the posts page tab to light up when the posts page is selected. Reasonable?
I have read the above posts and I have also read http://codex.wordpress.org/Pages#Using_a_Page_as_the_Front_Page_.28version_2.1.2B_only.29
But I can’t seem to make sense of it. Adding is_page(posts) to the line in my header.php file in the menu ul that looks like this: <li class=”<?php if ( is_page(posts) or is_home() or is_archive() or is_single() or is_paged() or is_search() or (function_exists(‘is_tag’) and is_tag()) ) { ?>current_page_item<?php } else { ?>page_item<?php } ?>”>/” title=”<?php echo get_option(‘k2blogornoblog’); ?>”><?php echo get_option(‘k2blogornoblog’); ?>
…doesn’t help at all.
Is that not where it should go?
