Let's say that for working you need space and you are using a theme with all thirty two workspaces defined. You don't need all that for usual personal use and decide to create a theme with only two workspaces. So you reduce the number of workspaces, set two new wallpapers, tweak colours a bit then save the new theme. This theme file will contain info not only for the two workspaces it is really using but also for the thirty others. These extras infos are of no use for this theme; they shouldn't be saved.
Perhaps is it also Screens app fault and these infos should be trashed as soon as the number of workspaces is reduced.
Let's say that for working you need space and you are using a theme with all thirty two workspaces defined. You don't need all that for usual personal use and decide to create a theme with only two workspaces. So you reduce the number of workspaces, set two new wallpapers, tweak colours a bit then save the new theme. This theme file will contain info not only for the two workspaces it is really using but also for the thirty others. These extras infos are of no use for this theme; they shouldn't be saved. Perhaps is it also Screens app fault and these infos should be trashed as soon as the number of workspaces is reduced.