Purim

How can Megilla 13b say the reason that Esther didn't reveal her nationality was because she was so Tznius? Esther 2,20 says explicitly that the reason that she didn't reveal her nationality was because Mordechai told her not to and she always does what Mordechai says ("ein Esther magedes es amah vi'es moladitah kaasher tzivah alehah Mordechai vies ma'amar Mordechai Esther osah ka'asher haysah bi'amnah itoh")! Clearly it has nothing to do with how Tznius she is, she just did it because she listened to Mordechai!