Is this something you've been able to do on this machine before, or is the machine new to you? There may be separate options for this function, one for use with just the stitch you have selected, and the other in the settings menu that's applied across the board. It also may be separate in the sewing function and the embroidery function. I have so rarely had reason to change it that I don't remember much about doing it, and my sewing/ embroidery machine is a Baby Lock, so my ideas aren't specific to your machine.
It might be worthwhile to switch between sewing and embroidery and back because the machine will have to reset some options between the two. Of course, as with any digital device, a restart might possibly help. I hope somebody comes along who knows more than I do about your Bernina.