Stop blocking selection-undo in read-only mode
Stop blocking selection-undo in read-only mode

Closes #4090

kerabromsmu/CodeMirror,sourcelair/CodeMirror,pabloferz/CodeMirror,codio/CodeMirror,xeronith/CodeMirror,mtaran-google/CodeMirror,kerabromsmu/CodeMirror,dperetti/CodeMirror,thomasjm/CodeMirror,ejgallego/CodeMirror,codio/CodeMirror,ficristo/CodeMirror,grzegorzmazur/CodeMirror,SidPresse/CodeMirror,MarcelGerber/CodeMirror,alur/CodeMirror,ejgallego/CodeMirror,crazy4chrissi/CodeMirror,alur/CodeMirror,dperetti/CodeMirror,SidPresse/CodeMirror,mtaran-google/CodeMirror,nightwing/CodeMirror,rrandom/CodeMirror,crazy4chrissi/CodeMirror,codio/CodeMirror,alur/CodeMirror,sourcelair/CodeMirror,nightwing/CodeMirror,grzegorzmazur/CodeMirror,grzegorzmazur/CodeMirror,jkaplon/CodeMirror,Dominator008/CodeMirror,wingify/CodeMirror,INTELOGIE/CodeMirror,mizchi/CodeMirror,MarcelGerber/CodeMirror,bfrohs/CodeMirror,schanzer/CodeMirror,pabloferz/CodeMirror,notepadqq/CodeMirror,jkaplon/CodeMirror,bfrohs/CodeMirror,mizchi/CodeMirror,schanzer/CodeMirror,hackmdio/CodeMirror,adobe/CodeMirror2,thomasjm/CodeMirror,hackmdio/CodeMirror,rrandom/CodeMirror,wingify/CodeMirror,namin/CodeMirror,SidPresse/CodeMirror,Dominator008/CodeMirror,sourcelair/CodeMirror,MarcelGerber/CodeMirror,jkaplon/CodeMirror,schanzer/CodeMirror,kerabromsmu/CodeMirror,wingify/CodeMirror,namin/CodeMirror,thomasjm/CodeMirror,INTELOGIE/CodeMirror,adobe/CodeMirror2,pabloferz/CodeMirror,nightwing/CodeMirror,ficristo/CodeMirror,TDaglis/CodeMirror,rrandom/CodeMirror,jayaprabhakar/CodeMirror,adobe/CodeMirror2,xeronith/CodeMirror,ficristo/CodeMirror,dperetti/CodeMirror,ejgallego/CodeMirror,bfrohs/CodeMirror,crazy4chrissi/CodeMirror,jayaprabhakar/CodeMirror,Dominator008/CodeMirror,mizchi/CodeMirror,TDaglis/CodeMirror,jayaprabhakar/CodeMirror,notepadqq/CodeMirror,TDaglis/CodeMirror,mtaran-google/CodeMirror,notepadqq/CodeMirror,INTELOGIE/CodeMirror,namin/CodeMirror,hackmdio/CodeMirror,xeronith/CodeMirror