Fix: loss of workspace data when switching between toolbox category types, fixes #1480 (#1529)
Fix: loss of workspace data when switching between toolbox category types, fixes #1480 (#1529)


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