Hide 'show blocks' button when no main.blocks
Hide 'show blocks' button when no main.blocks

switch-education/pxt,switch-education/pxt,Microsoft/pxt,switch-education/pxt,switchinnovations/pxt,switch-education/pxt,Microsoft/pxt,Microsoft/pxt,playi/pxt,Microsoft/pxt,playi/pxt,switchinnovations/pxt,Microsoft/pxt,switchinnovations/pxt,switch-education/pxt,playi/pxt,switchinnovations/pxt,playi/pxt