When other people are paying to enjoy a nice meal, it is hard to endure a child screaming in a high chair in a restaurant. I suggest taking your toddler outside during temper tantrums. You do not have to give her attention while doing this. Give her one warning. And if she doesn't comply, just calmly pick her up, with no words, and take her outside or somewhere where she can sit safely until she composes herself, such as her car seat (with you in the car, ignoring her.) When she calms down, then you tell her there is no screaming allowed in a restaurant and return to the table. If she does it again, repeat—again, without emotion.
If that doesn't work, you may need to avoid restaurants for a while until your toddler is older (or find a sitter so you can go out for a much needed break with grown-ups)! Imagine a night without toddler temper tantrums!
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