So I'm currently practicing how to use commas properly and have just come across the following example:
Jillian, who had worked in the dress shop all summer, hoped to work there again during the Christmas holidays.
As far as I know, commas here are used to set off a non-essential clause that doesn't add any essential meaning to the sentence. One would argue that commas are not needed here since the clause between the two commas is essential and removing it will affect the meaning of the sentence. Am I right?