Function tree_row 

pub fn tree_row(theme: &Theme, row: &Row, selected: bool, cursor: bool) -> Div

One row: its guides, its chevron, and then whatever the caller puts in it.

selected is what the app considers chosen; cursor is where the keyboard is. Two tones, the same pair crate::popover::menu_row_nav uses, so a tree and a menu never look like two different products.