If you right mouse click on a SUB TAB agives users multiple choices, select EDIT,
Figure 1: SUB TAB Pop-Up
it will bring up the SUB TAB Edit Control Button window
Figure 1: SUB TAB Pop-Up Edit Control Button window
This window will allow you to change the text on the button as well as the color.
It also allows you to set the color you have chosen to be the default color for any panel buttons you create on this sub tab
You can also choose to have all the buttons changed to the default color