There seems to be a problem with the configuration view for the Tax By Country & State & Zip plug-in. I'm curious if anyone else is seeing this. I am using v2.20 w/ SQL 2008.
In the administration site click Configuration/Tax/Tax Providers and click the configure link for the Tax By Country & State & Zip row. Everything looks fine until I enter a couple new tax rate records. I don't think the values of the new records matter but after entering a couple records the Telerik grid does some strange things. Try editing, updating, or deleting a row or 2. I have screenshots if the strange behavior is not reproducible or not apparent.
Thanks!