<img src="http://screensnapr.com/e/O8j1Y0.png" border="0" />
This happens after I re-name the animation frame, close the sprite-editor, then re-open the sprite-editor and click on the animation. It doesn't affect in-game, but it's just a sprite-editor bug.
-1 Less bug <img src="smileys/smiley4.gif" border="0" align="middle" />