How to choose an exact font colour for a style?

Using Impress 5.1.6.2 (via Linux Mint).

When I change the font colour via the toolbar, I can choose a custom colour, which allows me to enter a colour by ie. hex value or CMYK value. However, I cannot find how to do this when I want to change a style to use this colour, as that only allows me to choose a colour from a list. It’s a bit confusing that there seem to be different font colour choosers.

How do I change a style to match the colour I chose via the colour chooser in the toolbar?

It is changed in 5.3. The color chooser there allows using custom color.