How to change value label colours in Graph Builder

[#1]

I have created a chart with stacked bars, showing value labels on each segment of the stack. The default font colour is black (it seems). I want to make them white on this one graph. I have spent way to much time ineffectually poking around in preferences and other likely places but cannot find out how to make this simple change. I know it will be obvious and I will hang my head in shame but I need the help of some kind soul.

[#2]

Could you share a picture?

[#3]

Sure. Here is an example with black type for the number labels.

[#4]

I'd suggest you go to file > preferences > platform > graph builder. Then adjust your settings. Tick the boxes you're interested to change. You may reset them back to default if there's anything abnormal. Feel free to let me know how it went