Windows caption buttons take the bar's height less its hairline, a new token, instead of their row's, so they keep their height beside caps that wrap below them. A title bar's title is an Ellipsis: on Windows it takes the free width before the buttons and gives way; a centered title sits inset past the lights on both sides. The controls never shrink. Tests hold a long Windows title's close button inside a 280px bar and wrapped caps inside their row. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>