I've found that after the changes to the navigation block for MDL-27809, the categories listed in the Navigation block's "Courses" list come and go. Before that change, all the top-level categories were listed. Now, if I'm in a course then some categories will be missing. I haven't been able to figure out exactly what configuration options are necessary to make this come and go, but I have been able to create a test setup that causes this problem:

Create this hierarchy of categories and courses:

Category 1

• Category 1.1
  • Course 1.1a
  • Course 1.1b
  • Course 1.1c
• Category 1.2
  • Course 1.2a
  • Course 1.2b
  • Course 1.2c
• Course 1a
• Course 1b

Category 2

• Course 2a

Turn on $CFG->navshowcategories and $CFG->navshowallcourses, and set $CFG->navcourselimit to 5.

Now, from the /course/index.php page or other site pages, you'll see all the courses and categories listed in the Navigation block. However, if you navigate to course 1.2c, You'll find that Category 2 no longer shows up in the Navigation block.

The expected behavior is that Category 1 and Category 2, as the top level categories, should show up on every page. Or there should at least be a "Show all courses/categories" link to indicate that some categories are hidden.

If I revert commit e26507b361969c3e1f1f, then I find that it behaves as expected, and all the categories are shown when I'm in course 1.2c.