Always expand first item if no groups expanded
Always expand first item if no groups expanded

- Issue MatterHackers/MCCentral#3022
Ensure at least one SectionWidget expanded

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