Selection range is incorrect when selecting across multiple elements

Phenomenon

Selecting across nested block structures causes the Selection API to report inconsistent boundaries. Visually, the highlight looks correct, but programmatically, the anchorNode or focusNode can jump to the parent container instead of the leaf text node.

Reproduction Steps

1. Create two paragraphs: <p>One</p><p>Two</p>.
2. Select from the middle of “One” to the middle of “Two”.
3. Call window.getSelection().getRangeAt(0).
4. Observe that startContainer might be the parent div instead of the first <p>.

Observed Behavior

Edge/Chrome engines sometimes optimize range calculations by collapsing boundaries to the nearest common block, losing the fine-grained text offset.