Fixed crash when turning on shells visibility in preview and the application was started with background processing active
Fixed crash when turning on shells visibility in preview and the application was started with background processing active

prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r