Left-click on a node in the model hierarchy to navigate to that node.
Right-click on a node to collapse/expand it. Alt-right-click on a node with variables to select which ones to hide.
Note: Right-click in Firefox displays a browser menu. To disable that, visit about:config and set dom.event.contextmenu.enabled to true.
Hover over any cell in the matrix to display its connections as arrows. Click that cell to make those arrows persistent.

Toolbar Help