in src/component/selection/getDraftEditorSelectionWithNodes.js [139:150]
function getLastLeaf(node: any): Node {
while (
node.lastChild &&
// data-blocks has no offset
((isElement(node.lastChild) &&
node.lastChild.getAttribute('data-blocks') === 'true') ||
getSelectionOffsetKeyForNode(node.lastChild))
) {
node = node.lastChild;
}
return node;
}