[OS X TeX] ^ completion

[facenda at us.es]

 Hi all
I have installed TexShop 2.29 and I have a problem with autocompletion.
When I write in my file ^ I obtain ^^{} that is, two simbols ^ with the cursor between the brackets. I have to delete the additional ^ symbol. However, the subindex completion works well, when I type _ I obtain _{cursor here}.
Any hints to solve this problem would be appreciated.
Thanks in advance