allowiong pop ups in opera?

Hi, I recently downloaded Opera as I wanted to try a new browser, I got sick of Firefox and refuse to use IE. Anyway I am noticing with Opera that it wont allow pops ups from sites I have said it can. I have gone into the prefrences of Opera, gone down to the content tab and went into "manage site prefrences" When I have added a site and set it to "open all popups" it still does not allow the pop ups. I play Yahoo pool and I am noticing this when it comes to allowing pool tables to come up. Anyone got any ideas why it is doing this, thanks