Instead of using sidebar widgets to tell on what page they should be visible, I like to choose at the menu settings to appear on specific pages.
Default Wordpress way:
So projects is a page and has some subpages. But what if I have like 10 more of these pages and subpages with the same situation.
I would like to add an extra setting (a list of the top level pages):
But I cannot find any documentation, actions, filters etc when these settings are loaded.