Only 3 widgets per type allowed in my sidebar??

Hello,

I am redesigning an old site using this theme, and I came across a strange problem today. It seems in my main sidebar content, I can only add 3 widgets per type before the widgets just don’t display. I am not getting any code errors, the widgets just aren’t on the page anywhere if I try to add a fourth.

For example, I had three text widgets, and when I tried to add a fourth, nothing appeared. I moved on to use PHP widgets, and again, after three, the fourth won’t show up. Is this a setting that can be changed somewhere?