The trigger is a focusable element and participates in the standard tab order, responding to Tab and Shift+Tab key events per native browser behavior, i.e., these keys step through the browser tabindex sequence.

When the component is disabled it is removed from the tabindex sequence. VoiceOver's virtual cursor (swipe navigation) can still encounter the component, but standard keyboard Tab navigation skips it.

When the bib is collapsed, the bib content is excluded from the tab sequence. When expanded, focusable elements within the bib content are included in the natural tab order. In fullscreen mode, focus is trapped within the bib, and the tab sequence cycles through the bib content focusable elements until the bib is closed or the viewport no longer meets the fullscreen condition and is rendered as a popover.

When the desktopModal attribute is set, focus is also trapped within the bib on desktop viewports. All sibling elements on the page are marked inert, preventing interaction with content outside the dropdown until it is closed.