- I will try to explain the issue without making it even more confusing.
In short, there is no way to
- make ST mode always use area selection in both Xray and Solid modes, according to classic ST behaviour
- and make noST mode use facedots selection in Xray, and area selection in Solid, according to Blender defaults behaviour
so switching ST button you always have to switch Xray facedot checkbox as well to achieve such a differentiation, in case if user want to keep Blender default behaviour extended by classic ST mechanics.
If there will be ability to force face area selection for ST (simultaneously, both in Xray and Solid modes), such a differentiation can be achieved, and it will be possible to switch between (and indicate) those modes via single button.
Hope it sounds more clear.