Multiple Captions inside cells,
Nav. 4.0: last one takes effect, and close td tr.
previous captions are totally ignored.
If there were no caption3, caption2 would take effect.
Xena 6.0: Ignore misplaced caption tag, contents treated as text.
cell 1-1 | cell 1-2 |
cell 2-1 | cell 2-2 |