After selecting "Value Highlighting" in Options>Calc>View the selected foreground (text) colour is ignored when displaying a calc sheet for text as well as values and formula results, and always displays as black irrespective of the background colour. Selecting Format>Cell>Font Effects displays the correct foreground and background colours.
I think the enhancement request bug 53826 covers your issue. *** This bug has been marked as a duplicate of bug 53826 ***