When adding columns to the list of central columns, choosing a different table from the table dropdown does not clear the list of columns of the previous table from the columns dropdown.
Fixed with https://github.com/phpmyadmin/phpmyadmin/commit/f07fc445929fcbc91cc983a810121d4856df70ba
Fixed with https://github.com/phpmyadmin/phpmyadmin/commit/f07fc445929fcbc91cc983a810121d4856df70ba