In twos and threes the rest of the group took their leave, too. Cho made rather a business of fastening the catch on her bag before leaving, her long dark curtain of hair swinging forwards to hide her face, but her friend stood beside her, arms folded, clicking her tongue, so that Cho had little choice but to leave with her.
Harry Potter and the Order of the Phoenix
Is "made rather a business of" a set phrase? I can't find it in any dictionaries. I guess here it means: Cho deliberately procrastinated by slowly fastening the catch on her bag before leaving. Is this understanding correct?