I think I have found a bug with creating a new style.
Start with a blank style canvas to define a new style - a treeless dual vertical in this case. Everything seems to work except if you set a Tab Group for the right lister - it is ignored when selecting the new style from the drop down menu. What happens is that you get an 'Empty Tab' in the right lister - presumably because no folder has been defined in the Folder option below Tab Group.
If you deselect the Tab Group option and then tick and select a folder to be displayed in the right panel then that works OK. Now go back and tick the Tab Group option again and when you select the new style, you get the previously defined folder instead of the Tab Group if the Folder option is still ticked but greyed out. If the Folder option is unticked before selecting the Tab Group option, then you're back to an 'Empty Tab'.
I can repeat it also by modifying the default Dual Vertical style.