You've likely inadvertently enabled "Touch-Mode." In touch mode we make this switch since the drop down portion of the split button is extremely narrow and difficult to pick with a finger.
To toggle touch mode, just click it in the view menu:
That did it! Many thanks!
Thank you for the explanation. Often we wonder why SW would ever do something as inefficient as that..... This information makes perfect sense and is something I would have never thought of.