I don't understand how 限る is used here in the left panel. My guess is that she's saying "For someone with such a plain face, she's got a bad personality". Here 限って would correspond to the "For someone with..." part in English, basically assigning a certain quality to someone. And the rest of the sentence basically expresses surprise that someone with such quality (plain face) would act in this way (with a bad personality).
Is this correct or am I way off?