Check if self._comm is None before trying to select a file... (cherry picked from commit 5631a45)
Check if self._comm is None before trying to select a file...
(cherry picked from commit 5631a45)

alex1818/OctoPrint,Jaesin/OctoPrint,Skeen/OctoPrint,beeverycreative/BEEweb,shaggythesheep/OctoPrint,eddieparker/OctoPrint,mayoff/OctoPrint,MaxOLydian/OctoPrint,Voxel8/OctoPrint,spapadim/OctoPrint,shohei/Octoprint,javivi001/OctoPrint,d42/octoprint-fork,leductan-nguyen/RaionPi,eliasbakken/OctoPrint,uuv/OctoPrint,madhuni/AstroBox,chriskoz/OctoPrint,bicephale/OctoPrint,Salandora/OctoPrint,abinashk-inf/AstroBox,rurkowce/octoprint-fork,jneves/OctoPrint,JackGavin13/octoprint-test-not-finished,AstroPrint/AstroBox,ryanneufeld/OctoPrint,Catrodigious/OctoPrint-TAM,MaxOLydian/OctoPrint,ryanneufeld/OctoPrint,ymilord/OctoPrint-MrBeam,Salandora/OctoPrint,aerickson/OctoPrint,mcanes/OctoPrint,nicanor-romero/OctoPrint,beeverycreative/BEEweb,dragondgold/OctoPrint,ymilord/OctoPrint-MrBeam,uuv/OctoPrint,JackGavin13/octoprint-test-not-finished,Salandora/OctoPrint,masterhou/OctoPrint,eliasbakken/OctoPrint,punkkeks/OctoPrint,MoonshineSG/OctoPrint,mcanes/OctoPrint,Skeen/OctoPrint,Catrodigious/OctoPrint-TAM,leductan-nguyen/RaionPi,sstocker46/OctoPrint,Javierma/OctoPrint-TFG,EZ3-India/EZ-Remote,CapnBry/OctoPrint,sstocker46/OctoPrint,MoonshineSG/OctoPrint,DanLipsitt/OctoPrint,punkkeks/OctoPrint,markwal/OctoPrint,aerickson/OctoPrint,dragondgold/OctoPrint,MoonshineSG/OctoPrint,CapnBry/OctoPrint,madhuni/AstroBox,MolarAmbiguity/OctoPrint,madhuni/AstroBox,C-o-r-E/OctoPrint,nickverschoor/OctoPrint,MolarAmbiguity/OctoPrint,C-o-r-E/OctoPrint,Mikk36/OctoPrint,masterhou/OctoPrint,nickverschoor/OctoPrint,Mikk36/OctoPrint,skieast/OctoPrint,dansantee/OctoPrint,senttech/OctoPrint,abinashk-inf/AstroBox,bicephale/OctoPrint,eddieparker/OctoPrint,foosel/OctoPrint,jneves/OctoPrint,EZ3-India/EZ-Remote,dansantee/OctoPrint,JackGavin13/octoprint-test-not-finished,mcanes/OctoPrint,CapnBry/OctoPrint,javivi001/OctoPrint,abinashk-inf/AstroBox,chriskoz/OctoPrint,SeveQ/OctoPrint,ryanneufeld/OctoPrint,ymilord/OctoPrint-MrBeam,dragondgold/OctoPrint,dansantee/OctoPrint,nicanor-romero/OctoPrint,alex1818/OctoPrint,EZ3-India/EZ-Remote,Jaesin/OctoPrint,shaggythesheep/OctoPrint,masterhou/OctoPrint,Voxel8/OctoPrint,AstroPrint/AstroBox,Jaesin/OctoPrint,abinashk-inf/AstroBox,skieast/OctoPrint,senttech/OctoPrint,shohei/Octoprint,madhuni/AstroBox,Javierma/OctoPrint-TFG,Catrodigious/OctoPrint-TAM,bicephale/OctoPrint,mayoff/OctoPrint,alex1818/OctoPrint,spapadim/OctoPrint,Voxel8/OctoPrint,Javierma/OctoPrint-TFG,shohei/Octoprint,ErikDeBruijn/OctoPrint,punkkeks/OctoPrint,Salandora/OctoPrint,javivi001/OctoPrint,JackGavin13/octoprint-test-not-finished,chriskoz/OctoPrint,MolarAmbiguity/OctoPrint,nickverschoor/OctoPrint,beeverycreative/BEEweb,foosel/OctoPrint,Jaesin/OctoPrint,ymilord/OctoPrint-MrBeam,ymilord/OctoPrint-MrBeam,EZ3-India/EZ-Remote,ryanneufeld/OctoPrint,leductan-nguyen/RaionPi,Mikk36/OctoPrint,skieast/OctoPrint,DanLipsitt/OctoPrint,leductan-nguyen/RaionPi,CapnBry/OctoPrint,Javierma/OctoPrint-TFG,ErikDeBruijn/OctoPrint,beeverycreative/BEEweb,spapadim/OctoPrint,ErikDeBruijn/OctoPrint,shohei/Octoprint,uuv/OctoPrint,foosel/OctoPrint,aerickson/OctoPrint,Skeen/OctoPrint,shaggythesheep/OctoPrint,MaxOLydian/OctoPrint,nickverschoor/OctoPrint,eddieparker/OctoPrint,mayoff/OctoPrint,C-o-r-E/OctoPrint,chriskoz/OctoPrint,bicephale/OctoPrint,markwal/OctoPrint,markwal/OctoPrint,sstocker46/OctoPrint,d42/octoprint-fork,mrbeam/OctoPrint,senttech/OctoPrint,SeveQ/OctoPrint,shohei/Octoprint,AstroPrint/AstroBox,mrbeam/OctoPrint,mrbeam/OctoPrint,rurkowce/octoprint-fork,nicanor-romero/OctoPrint,MoonshineSG/OctoPrint,eliasbakken/OctoPrint,senttech/OctoPrint,jneves/OctoPrint,foosel/OctoPrint,SeveQ/OctoPrint