Don't use position: fixed in context-menu hack
Don't use position: fixed in context-menu hack

It doesn't work inside of a transformed container, even for zero
transforms (which some components seem to love putting on root
elements, for whichever reason)

Closes #3238

INTELOGIE/CodeMirror,pabloferz/CodeMirror,SidPresse/CodeMirror,jkaplon/CodeMirror,Jisuanke/CodeMirror,grzegorzmazur/CodeMirror,hccampos/CodeMirror,alur/CodeMirror,hccampos/CodeMirror,jayaprabhakar/CodeMirror,Jisuanke/CodeMirror,sourcelair/CodeMirror,grzegorzmazur/CodeMirror,namin/CodeMirror,MarcelGerber/CodeMirror,thomasjm/CodeMirror,ashmind/CodeMirror,Dominator008/CodeMirror,crazy4chrissi/CodeMirror,vincentwoo/CodeMirror,adobe/CodeMirror2,mtaran-google/CodeMirror,sourcelair/CodeMirror,wingify/CodeMirror,hackmdio/CodeMirror,pabloferz/CodeMirror,codio/CodeMirror,alur/CodeMirror,ashmind/CodeMirror,ejgallego/CodeMirror,Jisuanke/CodeMirror,jayaprabhakar/CodeMirror,antimatter15/CodeMirror,nightwing/CodeMirror,notepadqq/CodeMirror,xeronith/CodeMirror,thomasjm/CodeMirror,hccampos/CodeMirror,bfrohs/CodeMirror,adobe/CodeMirror2,ficristo/CodeMirror,TDaglis/CodeMirror,schanzer/CodeMirror,INTELOGIE/CodeMirror,hackmdio/CodeMirror,bfrohs/CodeMirror,MarcelGerber/CodeMirror,ejgallego/CodeMirror,kerabromsmu/CodeMirror,codio/CodeMirror,dperetti/CodeMirror,dperetti/CodeMirror,alur/CodeMirror,notepadqq/CodeMirror,mtaran-google/CodeMirror,TDaglis/CodeMirror,rrandom/CodeMirror,mizchi/CodeMirror,InternetGuru/CodeMirror,xeronith/CodeMirror,ficristo/CodeMirror,hackmdio/CodeMirror,Dominator008/CodeMirror,SidPresse/CodeMirror,wingify/CodeMirror,TDaglis/CodeMirror,pabloferz/CodeMirror,antimatter15/CodeMirror,notepadqq/CodeMirror,schanzer/CodeMirror,SidPresse/CodeMirror,namin/CodeMirror,rrandom/CodeMirror,nightwing/CodeMirror,wingify/CodeMirror,vincentwoo/CodeMirror,MarcelGerber/CodeMirror,grzegorzmazur/CodeMirror,bfrohs/CodeMirror,Dominator008/CodeMirror,antimatter15/CodeMirror,mizchi/CodeMirror,xeronith/CodeMirror,thomasjm/CodeMirror,InternetGuru/CodeMirror,crazy4chrissi/CodeMirror,mtaran-google/CodeMirror,kerabromsmu/CodeMirror,rrandom/CodeMirror,jkaplon/CodeMirror,kerabromsmu/CodeMirror,sourcelair/CodeMirror,adobe/CodeMirror2,vincentwoo/CodeMirror,jayaprabhakar/CodeMirror,dperetti/CodeMirror,mizchi/CodeMirror,jkaplon/CodeMirror,InternetGuru/CodeMirror,ejgallego/CodeMirror,codio/CodeMirror,schanzer/CodeMirror,crazy4chrissi/CodeMirror,ashmind/CodeMirror,namin/CodeMirror,nightwing/CodeMirror,INTELOGIE/CodeMirror,ficristo/CodeMirror