Fix nasty bug with new blockly drag optimisation and semantic ui (#1221)
Fix nasty bug with new blockly drag optimisation and semantic ui (#1221)


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