MonoGame UI Dropdown

A dropdown (combo box) shows a single selected item in a collapsed header. On click or Enter, it expands an overlay list below (or above if near the bottom of the screen). Selecting an item collapses the list and fires SelectionChanged. For complete code, read references/ui-dropdown.md.

Assumed Contract

Extends UIElement from monogame-ui-core. Receives pointer events from monogame-ui-interaction. Participates in focus via monogame-ui-focus. The expanded list is drawn as an overlay at the end of the UI Draw pass, always on top of other elements.

Two-State Architecture

Collapsed state:
  [Selected Item Text ▼]     ← draws as a single button-like element