Thanks very much. I did not know that Mostrar/Escondir might be an alternative to Mostrar/Ocultar. Is the latter considered more "geek-like" than the former? This is for a sixth-grade-level Flash educational application where a user must slide an informational window open and closed and where Open and Close are already the labels of commands that open and close files.
I wouldn't quite say "geek-like", but maybe a bit more "cultured".
However, such details can become a slippery slope as far as Spanish is concerned, because of the variety of countries that claim the most excellent language of Cervantes as their own.
Sticking my neck out , I'd say "esconder" over "ocultar" is a pretty good bet for use with children.