Annotation overlays should preserve access to source evidence

General lesson: evidence annotations should preserve access to the source they explain. For dense document fields, keep boxes as thin transparent outlines, hide opaque number badges until the individual marker is hovered or focused, and provide one reversible hide/show control in the expanded viewer. This pattern applies to OCR conflict overlays and similar review surfaces where labels can cover the exact evidence under review. Its limit is touch-only interaction: touch needs focus/tap support or the global toggle; hover alone is insufficient.