Q:

Menu tree from taxonomy terms and nodes which belong to them

i need to create a collapsible menu tree from taxonomy terms and nodes which belong to them (not nested terms, but content pages) i'm totally stuck about it  i've found solutions for nested taxonomy terms only, but not for combined with content pages from the term. meaning menu tree like this:

A:

It's very simple to create the tree structure output you're looking for: 

Create the Content type Views, 
add the Taxonomy term Field next to the Title field, 
under Format Views settings choose to group by the Taxonomy field Grouping field Nr.1

On the Taxonomy field choose Exclude from display. 
This will give you a list of nodes that are displayed in groups by their taxonomy terms. 
To make that structure collapsible you can use some special option for the Format, for example Views Accordion or Views tree. 

