While working on an image in affinity photo I came to a point where the 'new fill layer' layer menu option would add a new fill layer but without color and the fill color could not be changed. It seems this occurs when the last operation prior to adding the new fill layer is drawing a geometric shape with transparent fill. I don't know but perhaps this happens when other shapes are drawn with transparent fill too.
The work around is to either (1) add another geometric shape with non-transparent fill before adding the new fill layer or (2) after adding the new fill layer change the fill type to 'none' then to the desired fill type after which a color(s) can be selected.
Is there a better way to avoid adding a colorless fill layer?