[Typo3] regular Page module disappeared?

[Bing Du]

The backend of my site worked fine after installing the Templavoila 
extension.  I noticed with Templavoila installed, there are two Page 
modules listed under Web.  One has a green icon and the other has a 
white icon.  Then don't know what I did, when I checked the module list 
again, the regular Page module (the one with a white icon) disappeared. 
  Anybody know what might have caused that?

Thanks,

Bing