Shadow DOM's Hidden Advantage: Building Tooltips Without Compromise

The choice between Shadow DOM and iframe reveals a fundamental tradeoff in browser extension design. While iframe isolation seems appealing, it breaks the visual experience by cutting off inherited fonts, forcing developers to reload fonts and causing unstyled-content flashes. Shadow DOM elegantly solves this by participating in the host page's font-loading lifecycle, maintaining visual consistency with just the tradeoff of explicit CSS property declarations—a small price for seamless tooltips.