It would be nice if you could open up sub-categories using the + sign without changing the page and unexpanding the section you were already in.

Take this page for example:
https://docs.mongodb.com/manual/reference/operator/query/

As it sits now, you cannot open up both the Comparison Query Operators and the Evaluation Query Operators to compare what are contained in both subcategories. Once you click the + sign, it takes you to a new page and collapses any previous category that was open.

Steps to Reproduce:
1) Open https://docs.mongodb.com/manual/reference/operator/query/
2) Click the + sign under Element Query Operators
3) Click the + sign under Query Operator Array

What I expect should happen:
I should stay on the same page, and the subcategory should expand. This would allow me to look at multiple query operator names in different categories.

What happens:
I click the + sign and it loads a new page. On the new page, only the subcategory you clicked on is expanded.