Another vote of confidence for Robins boss
Johnson quit Yeovil Town in order to join the club, but has won just three of his 13 games in charge.
Sextone has again defended his boss, despite renewed criticism from the terraces.
"Gary Johnson's position at the club is not an issue, he's only two months into a long-term contract," Sexstone said.
"We have no doubts at all about Gary, he has our full support. He is a great manager and that is why he got the job."