How do I use the fractional mode on the PLLs in STM32CubeIDE or STM32CubeMX?

[CKlib]

Good day,

How do I use the fractional mode on the PLLs in STM32CubeIDE or STM32CubeMX?

If I enter a number in the "fracnx" field there is a change but CubeMX still thinks the VOC frequency is to high due to the large DIVN value.

Thanks,

Charles