Another thing to try is to eyeball your entire category list, including hidden categories. Some folks have reported corruption in that list which caused problems. It manifests as an oddball category, often with a name like ACCT_2345. That bogus category can safely be deleted.
I just tried to reproduce this and could not. My Tax Summary report correctly shows Schedule E:Legal & professional fees. So you might have data corruption and a Validate & Repair might help.
If the transactions are in banking (not investment) accounts, you can try right-clicking them and choosing Tax line item assignments from the menu. You can assign a TLI directly to a transaction that way. Maybe it will work.