Never mind, I found out what was the issue... when you click on the Parts and Staves add icon, you have to make sure you right click on the small arrow portion of the icon, not the main body of the icon, and then you see a drop-down list which shows the different types of staves you can add. That should be changed so you can right click anywhere on the icon, or at least, don't automatically add music staves when the icon is clicked, just have the drop-down list show up in all cases. I wasted a lot of time before luckily stumbling upon the small area of the icon where the down arrow resides.