How to create sidebar?

Let me check, you build three user widget(wPanel, wPanelentry, wAnimatedPanelParent).
And then you build the blueprint in wPanel widget, right?
As a result, we expand the panel by this blueprint structure, right?
But I get lost in part of “We collapse the text pieces with a mouse click:”
I can not create the “on mouse button down” and “Return node”.