No matter how small or big the issue... I want things to work as they are intended to. For me (testing this) I didn't encounter the problem you describe... other than the very default colours showing up even when default colours had been changed, when choosing "Selected Hotspot" settings... and making the changes for colours absolutely permitted me to change to black. From the sound of it, you have encountered a bug, and I would be interested in having it located and eliminated.
Can you possibly strip down the project to the absolute minimum, save it and link me to the .ffc file?
Even though this may sound like a miniscule problem, it *could* potentially cause other issues if it is *wrong enough*.... therefore my invested interest in it

My destiny isn't carved in granite ...
It's written with a stick in dry sand ... on a stormy day ...
Trausti