rowTooltipBuilder property
Builds a card shown while the pointer is anywhere over a Node's rendered
row. Return null for a Node that should not have one.
Distinct from the per-Tier label tooltip on NodeTooltipTheme, which
attaches to the Node's icon-and-label content and explains the label. This
one attaches to the whole row and explains the Node.
The card is anchored at the pointer, and that is the one thing rowTooltipTheme cannot change: a row is as wide as the tree's content, which can exceed the viewport, so the visible part of the row's rect is the whole width of the view, and its centre is not where the user is looking. Anchored to the row, the card would open mid-view wherever the row is hovered.
By default the tooltip draws no surface of its own — no background,
padding, or elevation — because a card draws one. Return a Card, not a
bare Text, or give rowTooltipTheme a surface.
Implementation
final Widget? Function(BuildContext context, Node<T> node)? rowTooltipBuilder;