Although I did a thorough research I could not find a solution. Only solutions coming close.
My custom menu (“top”) shows this structure (you see a part of it):
page 1 subpage 1.1 category A subsubpage 1.1.1 subsubpage 1.1.2 subpage 1.2 category B subsubpage 1.2.1 subsubpage 1.2.2 subpage 1.3 category C subsubpage 1.3.1 subsubpage 1.3.2 page 2 page 3
Without using CSS (the real structure is by far bigger) I would like to display this in the sidebar, when a user currently looks at page 1 (only its children items):
subpage 1.1 subpage 1.2 subpage 1.3
And when the user currently looks at subpage 1.1 or any of its custom menu children (incl. posts in category A):
subpage 1.1 category A subpage 1.1.1 subpage 1.1.2 subpage 1.2 subpage 1.3
To put it in words:
Visible menu items:
I tried a few Custom Walker classes presented in that forum, none of them did the trick.
I also tried the plugin Advanced Menu Widget (http://wordpress.org/extend/plugins/advanced-menu-widget/), which comes very (!) close, but there seems to be a bug in it. Use of these settings would do the job generally:
Unfortunately it does not provide the result looking at category A or it’s posts in my example.
Thank you in advance.
Using the plugin “Advanced menu widget” by Ján Bočínec one can get pretty close. With one big exception: when you look at a post from category A, the whole sub-menu vanishes (except for a remaining empty <ul></ul>-construct).
So we are still looking for a working solution. We are going to try it now with Gecka submenu plugin and tons of CSS. But I am afraid that even this plugin does not provide enough CSS classes.
Thus this is half an answer 😉