chat tabs are larger

It appears the chat tabs in the chat window are larger. This is not my imagination: I used to be able to have three tabs showing (of whatever number were up) and now I only show two.

Is there a reason for larger chat tabs? Weren't they big enough before? Not only is screen space limited (making something which worked fine in a smaller size larger is a no no in this context), but being able to have three tabs visible versus the two currently visible is a reduction in functionality; why?

I will add: I play on OS X client (in case this makes a difference).