Base class for box containers.
- int alignment - The alignment of the container’s children (must be one of ALIGN_BEGIN, ALIGN_CENTER, or ALIGN_END).
- ALIGN_BEGIN = 0 — Aligns children with the beginning of the container.
- ALIGN_CENTER = 1 — Aligns children with the center of the container.
- ALIGN_END = 2 — Aligns children with the end of the container.
Arranges child controls vertically or horizontally, and rearranges the controls automatically when their minimum size changes.