I was giving an answer, but perhaps I didn't make myself clear enough.
Here it is again, hopefully clearer:
You're asking for a one-line answer for a question that isn't easy to answer in entire books on the topic, let alone a paragraph.
You're also asking a question that Popper answered extensively in the exact same work where he wrote about the Paradox of Tolerance,
The Open Society and Its Enemies.
You're a smart cookie, you can figure it out.
EDIT: If you actually want to learn more, the Stanford Online Encyclopedia of Philosophy extensively discusses different approaches of the issue of tolerance and toleration in this article here:
Toleration (Stanford Encyclopedia of Philosophy)