DMO Selection Live Visualizer

This page leaves dmo-selection-cause-lab.html untouched and focuses on one visual question only: where does window.getSelection() say the caret is, and how far is that from the logical text end that the blinking cursor appears to use after the BeefText replacement?

Live Editor Monitoring

JS logical offset- Content end- Delta px-

JS selection geometry Logical content-end geometry

Recommended reproduction: click Empty Root, dictate hy0, let BeefText replace it, then watch the red JS marker and the green END marker. If the DOM selection goes stale, they split apart immediately.