Execute container reloads on UIThread
Execute container reloads on UIThread

- Issue MatterHackers/MCCentral#1836
Index out of range exception on startup

unlimitedbacon/MatterControl,larsbrubaker/MatterControl,mmoening/MatterControl,larsbrubaker/MatterControl,larsbrubaker/MatterControl,jlewin/MatterControl,unlimitedbacon/MatterControl,mmoening/MatterControl,unlimitedbacon/MatterControl,mmoening/MatterControl,jlewin/MatterControl,larsbrubaker/MatterControl,jlewin/MatterControl,jlewin/MatterControl,unlimitedbacon/MatterControl