Parent topics in topic tree behave differently in Topic List block and Dashboard Page Search

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Using the sample Blog Entries topic tree, I added the following nested topics:

- Sports
- Football
- Basketball

As a test, blog posts are tagged with either Football and/or Basketball, but not Sports.

In the Topic List block on the blog pages, clicking on either Football or Basketball will return a result page listing blog posts that have been tagged with either topic. However, clicking on Sports (the parent topic of both Football and Basketball) returns nothing.

In the Dashboard Page Search, using the Advanced Search to limit results by Football and Basketball gives the same results as the Topic List block. However, limiting by Sports returns all the posts tagged with Football or Basketball.

The behaviour of the Page Search seems to be logical for me (posts related to Football or Basketball also can be inferred to be related to Sports). Is there a way I could make the Topic List block also behave in this manner?

MrRonbot